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Produced by the NASA Center for Aerospace Information (CASI)
NASA TECHNICAL, MEMORANDUM NASA TM-77

ASTRONOMICAL OBSERVATORIES

D. N. Ponomarev

Translation of "Astronomicheskiye Observatorii",

(Novoye v zhizni, nauke, tekhnike, Seriya Kosmonavtik

Astronomiya, No. 6), Moscow, Znaniye Publishinq House

1983, pp. 1-64.

(RASA-TC-77295) ASTIRONOMIC hL UBSERVATORIES M84 -17082

(National heror,autic:s and Space

4:ministratiou) 17 p fi(: A05 /Me A01 CSCL 03A

Uric Ids

G3/89 18083

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

WASiiINGTON, D.C. 20546 OCTOBER 1983
1. loo""$ N NASt1 TM-77295 2. 69"-A "oil A.•...I« Nw ^, R..I^I.wt'. C.^.IN N.,

4. t6419 .od srbwlw (1ctC*)5er 1983

ASTRONOMICAL OBSERVATORIES 1. 006,I9,,,,4.Io,f,n6641160C640

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IL Typo .l R..«. end ► ..;.4 c...,.d ^^^^- rA q110&_ Translation

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tiona^ ^elooautics and Space Administration

Wasnington t D.C. 4546 1A. sN.•.^q Atomy Cod*

1f. 3.Nt.os.w.wr N...•

Translation of "Astronomiciheskiye Observatorii", (Novoye v

zhizni, nauke, tekhaike, Seriya Kosmonavtika, Astronomiya,

No. 6), Moscow, Znaniye Publishing House, 1983, pp. 1-64.

la. Abol,90 *

The pamphlet discusses the layout and equipment of astronomical observatories, the oldest scientific institutions

of human society. The example of leading observatories of

the USSR allows the reader to familiarize himself with both

their modern counterparts, as well as the goals and problem,

on which astronomers are presently working.

The book is aimed a.t a broad range of readers.

IF. Rq rood* (f.IMtN b AutwM14f

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Is. ol.rsbvn . Iopossn 11

THIS COPYRIGHTED SOVIET WORK IS REPRODUCED AND SOLD BY NTIS UNDER LICENSF

FROM VAAP, THE SOVIET COPYRIGHT AGENCY

NO FURTHER COPYING IS PERMITTED WITHOUT PERMISSION FROM VAAP.

1 e. 1,66" t, c l.. w f. t64 IM. op" 3k sti+..., ow C166011. (d *As peed $I& a ►.a« a Polity

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ORIGINAL PAGE 19

OF POOR QUALITY STANDAND TITLI ► Age
iii

Table of Contents

Pa

Introduction . . . . . . . . . . . . . . . . . . 

ALittle History . . . . . . . . . . . . . . . . . . . . . . 

Astronomical Instruments. . . . . . . . . . . . . . . . . 1

Astronomical observatories of the USSR. . . . . . . . . . . 3

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . 6

The Amateur Astronomer's Corner . . . . . . . . . . . . . 6
Introduction

Often my new acquaintances, discovering that T am an 

astronomer, will ask: "Well then, let's see the sky in your

telescope!" On hearing such a request, T am always somewhat

confounded. There is a natural interest in the studies of t

stars, nebulae, galaxies, quasars and other celestial object

a knowledge of the laws of formation and evolution of tae

universe, analysis of the multiplicity of forms of matter an

the phenomena which occur in it, in a word, everything concerned with astronomy. But it is not so easy to satisfy the

thirst of the curious.

r_ On the one hand, it is a technically difficult task. T

astronomers seldom look at the sky with the naked eye. The e

is too weak and limited in its capacity as a receiver of lig

Astronomical observations, all of which come back to gatheri

electromagnetic radiation from celestial objects, are done w

more sensitive and specialized receivers of radiation than t

human eye. These may be photoelectric ,receivers, television

equipment and so on. About 300 of all observations are done

through photography.

But even in those rare cases when visual observation is

done, i.e. with the unaided eye, the view is hardly impressi

r' usually only one or two stars are visible. Therefore, to

"show the sky" we must either rig up a special visual appara

or employ auxiliary telescopes or guides. But even the guid

of large telescopes are now photoelectric:.

r On the other hand, the sky is far from always clear. Q

*

Lumbers in the margin indicate pagination in the foreign te

f
often, it is overcast, and not only one, but several nights i

a row. And the program of observations of the astronomers is 

interrupted. They wait impatiently until it "clears". Every

minute counts and, as they say, "there isn't enough sky". An

so often, even in the dead of night, all it rakes is the sky 

clear suddenly for the astronomers to rise from bed and begin

observation. In many cases they do not even go to bed, but

wato.,h the entire night allocatf,:d to their observational progra

The objects of astronomical observations and their resea

methods are quite diverse. But one thing unites all astronome

That is their instrument, the telescope. These are quite uni

and of interest in their own right.. And these the astronomer

are quite ready to display to the curious, insofar as can be

done during the day or the off time.

Each telescope is a high precision, complicated instrumen

combining an optical system and a mechanical mounting. Variou

receivers of radiation and the required auxiliary equipment a

attached to it. Working with astronomical instruments require

appropriate forms of management. Such managing institutions a

the astronomical observatories. These, their specifics, the

problems on which astronomers are working and the instruments

they are using, will form the subject of this pamphlet.

A Little History

Lost in the remote2ast... Astronomy has always attende

mankind. The rising and setting of the Sun determined the rhy

of life, which is the biological rhythm of man. The round of

existence of the cattle-raising nations was set by the phases

of the Moon, that of agricultural peoples by the seasons of th

year. It was in fact practical concerns, especially orientat

in time and in space, which stimulated the rise of astronomica

2
knowledge.1

The Megalithic structures of Stonehenge, a remarkable ob

servatory-cum-temple (Fig. 1) in the southwest English plains

have survived from the Stone Age. It took a long time to buil

the erection of this ring-shaped structure was begun by the

people of the Stone Age, but completed by people of the Bronz

Age. The time for the construction spans 2800-1600 B.C.

Its main part is a ring roughly 30 m in diameter of ver- 

tically erect stone pillars weighing about 25 t. Inside the

ring there were five stone arches of blocks weighing about

50 t: two stories served as props, a third spanned them at th

top. The ring of stone pillars was bordered by a circular

trench of almost 100 m diameter, surrounded by embankments,

s as well as several intermediate rings marked by small stones

or ground craters. At the outside, 30 m beyond the bank, on

the axis of the horseshoe, there is a "heel" stone!, surrounded

by a small trench. It is thought to have been a reference,

lining up with sunrise of the summer solstice.

1

Stonehenge was both a temple and a prototype of the

astronomical observatory. Narrow opening's in the stone arches

not even large enough to fit the head, served as sights which

strictly fixed the bearing from the center of the structure

onto various points of the horizon and points of rising and

1Here is an example. Several years ago the Novosibirsk

archeologist V. Ye. Larichev, excavating a settlement of the

Paleolithic near Achinsk, found a staff with a ring of wooly

mammoth tusk. Both the staff an& the ring were covered with

spiraling snakelike bands, small recesses and an intricate

network of patterns. Studies of the staff revealed that its

images constitute an astronomical calendar - a peculiar calcu

lating device for counting the years and even predicting

eclipses. This staff belonged to people who lived in Siberia

18,000 years ago. As Larichev writes: "The significance and

combinatorial analysis of the remarkable numbers which they k

about are the highest compliment to the intellectual and arti

abilities of the ancient Siberians" (.Larichev, V. Ye., Peshche

charodei [Magicians of the Caves], Novosibirsk, 1980, p. 220)
f VOOV, QUR161-1

0

di LCh, nee ri

t^ jv

^J«

a Y

-upright stones

",stones lying or

gone

Fig. 1. Diagram of the Stonehenge

works: 1 - central so-called "altar"

stone, 4,8 x 1 x 0.5 m; 2 - main ring

of pillars; 3 - inner ring of small

"blue." stones; 4 - intermediate rings

of craters: the inner of diameter

40 m (30 craters), middle of diameter

53.4 m (also 30 craters) and outer ring,

opened by Aubry, with diameter of 88 m

(56 craters); 5 - horseshoe of largest

stone,).

setting of the Sun and Moon.. The ancient observers determined

and predicted the arrival of the summer and winter solstice,

the spring and autumn equinox and, perhaps, the times of lunar

and solar eclipses.

The need to establish a connection between certain

astronomical phenomena and everyday earthly events was especia

important for the agricultural nations of the ancient world

Egypt and the Near East. The serious scientific development

of astronomy is largely associated with the accomplishments of

4
the ancient Greeks, especially the representatives of the

Alexandrian School.

The city of Alexandria was founded in 332 B.C. The

Ptolemies, the rulers of Egypt, fostered the sciences and

poetry and assisted in the construction of a temple of the

muses - the Museion of Alexandria, a sort of academy of science

with munificent library, for which this institution became

famous. Its name (museion - museum) became a common noun. At

the museum of Alexandria the world's first scientific astronomi

observatory was created with which the names of all the promine

astronomers of the subsequent five centuries, beginning with

Aristarchos of Samos, are more or less connected.

After the fall of the Roman Empire and the spread of

Christianity, the development of science came to a halt in

Europe. The Alexandrian library and museum were destroyed.

For nearly a millenium, Western Europe fell into the gloom of

the middle ages. In contrast, in the East, in the Arabian

world, the sciences including astronomy underwent further

development. In the VIII-X centuries, the Arabs translated

nearly all the works of the ancient Greek astronomers. Large

observatories were constructed at Bagdad, Damascus and several

other cities.

on the territory of our country, in the outskirts of

Samarkand, the remains of the observatory of Ulugbek are pre- 

served. The grandson of Timur, ruler of the vast region of

Maverannakhra with its capital at Samarkand, and after 1447

ruler as well of all the extens •l ve domain of Timur, Muhammed

Taragai Ulugbek, availing himself of the perquisites of power,

attracted to Samarkand the leading scientists, astronomers 

and mathematicians. In 1430 ( according to others 1424.) he

built the largest astronomical observatory of the time, a 

round tower almost 50 m in diameter, having three stories and 
an observation platform on top. Through the entire tower,

embedded in the ground, along the meridian was situated the

chief astronomical instrument of that time a stone quadran

(others say a sextant), consisting of two marble-faced arcs

with a stairway between them. It is believed this gigantic

instrument was used to determine the angle of inclination of

the ecliptic to the equator, for observations of the Sun, Mo

and planets.

In 1449 the eldest son of Ulugbek, Abd-al-Latif, abette

by the reactionary clergy, treacherously slew Ulugbek as an

"apostate from Islam" and took power. Religious fanatics

plundered and destroyed the observatory. ) Only manuscripts

were rescued by Ulugbek's savants.

European observatories of the XVII and XVIII century. 

the second half of the XVII and early XVIII century, State

scientific observatories began to be founded in rapid succes

in Europe. The major geographical discoveries, and the nau

and land voyages, required a more exact determination of the

size of the globe, and new methods of determining time and

coordinates on land and on water. But the only more or less

reliable means of determining geographical position was deter

mination of latitude and longitude (introduced by the ancient

Greek astronomer Hipparchus) from astronomical observations.

Yet such determinations required a knowledge of the pointlike

celestial coordinates of the stars, planets and Moon, and use

of appropriate catalogues and tables. it was also necessary

to be able to determine and keep accurate time.

1 Only in 1908 did the Russian archeologist V. M. Vyatkin find

its remains, while in 1948 it was excavated and partially

restored by the efforts of V. A. Shishkin. The remaining

portion of the observatory is an unique architectural and

historical monument, carefully preserved by the government.

Alongside the observatory, a museum of Ulugbek has now been

created.

6
And so from the second half of the XVtx century in Europ

mainly on the initiative of the leading scientists, state

astronomical observatories came to be built. 1 Thus, in Fran

on the initiative of the astronomer J. p iccard, the "Sun King

Louis XIV advanced sums for constr,^,ction of the Paris observa

tory (the construction was begun in 1667 and continued until

1671). A magnificent building was put up, resembling a castl

with observation platforms on top. At the Paris observatory

many diverse astronomical observations were performed: four

satellites of Saturn and the darts line in its ring (the

so-called "fissure of Cassini") were discovered., while the

Danish astronomer 0. Roemer, invited to work at the Paris

observatory, proved the finite speed of light (from observati

of eclipses of the satellites of Jupiter) and estimated its

value. Not less and possibly more famous for the Paris obser

vatory was the diversified work on determining the precise

positions of the stars, as well as the dimensions of the Eart

During these same years in England a royal commission

headed b;► J. (G.?) Flemstead was petitioning for the creation

of an observatory in order to develop a rational method of

fixing longitude by determining the exact positions of the st

and Moon. Soon thereafter the king signed an edict founding

the observatory, to be kept at government expense, while

J. F1erlstead was nominated its director with title of "Royal

Astron.ormer". The observatory began to function in 1676 in th

London suburb of Greenwich. J. Flemstead acqui:ced some of th

instruments at his own cost, some were donated by wealthy

benefactors.

The chief merit of the observatory was the compilation o

a star catalogue, the first in a series of many Greenwich cat

logues now covering nearly 300 years. The importance of this

1 The first of these was the observatory of Copenhagen (built

from 1637 through 1656), although it burned down in 1728.
fundamental contribution to astronomy is coniinied by the fac

that the meridian passing through the Greenwich observatory i

taken as the zero long."tuder while the meats solar time of thi

meridian is taken as the International Time.

On account of the great illumination produced by Landon,

in 1951 the Greenwich observatory was moved to a rural locali

70 km southeast of London. The administrative headquarters a

laboratories were lodged in the venerable castle of Hearstmons

whose name became that of the new observatory.

After the founding of the Paris and Greenwich observator

many European nations began to build state observatories. Bu

along with these serious scientific organizations, private an

sometimes quite amateur obse Vatories appeared, confronting

other more modest tasks. The amateur observer did not need t

take accurate readings, All that was needed was attentive and

regular examination of the starry sky. Even so, not everyone

succeeded. But several of those who began as amateurs finish

as professi.onals and provided an important contribution to the

development of astronomy.

One of these was Charles Messier who, entering the emplo

ment of the astronomer J. Del.ille as copyist, gained access to

a small refractor when the latter returned from Ste Petersburg

observing the sky in search of comets, Messier discovered 14

comets in 40 years. His observatory was in the turret of his

Paris dwelling. In the course of his observations he also 

discovered 103 nebulous objects (68 of these for the first 

time) and in 1781 published a catalogue of these, so others

would not confuse them with comets. 

William Herschel, by profession a musician, became in

time an outstanding observational astronomer and optician. In

1773 he built a giant reflector with mirror diameter of 122 c

8
and focal distance of roughly 12 m (the mirror weighed about

2 t). But his major observations were done with reflectors 

having mirror diameters of 30 cm, or. later 47.5 cm (with foca

distance 6 m). Being an optician, he made a new advance in

telescope construction, although his telescopes were set up

on a troublesome azimuth mounting, with poor aiming and no

clockwork. But Herschel was little concerned with star coordinates. He was more interested in the pattern of the Univer

structure.

At his home observatory in Sloe, near Windsor palace, he

discovered that the majority of the nebulae from the list of

Messier could be resolved into stars - they were stellar clust

To Herschel belongs the discovery of a new class of nebulae,

named by him the planetary nebulae. He discovered more than

800 binary and multiple stars, showing that several of them

form physical systems.

An even larger, but equally awkward reflector was built

by W. Parsons, bearing the title of Lord Ross, on his estate

Byor Castle in Ireland. His reflector had a mirror diameter

of 182 cm and focal distance 15.6 m. With its help, Parsons

discovered many details of the structure of nebulae, including

the spiral structure of several of them. He studied the Grea

Nebula in Orion and observed several details of the surfaces

of the planets. 1

The St. Petersburg astronomical observatory. The conque

of the immense territories of Siberia, the Far North, and the

maritime voyages of the pomors in the XVI-XVIII centuriest

The famous astronomer 0. V. Struve, son of the founder and

afterwards himself the director of the Pulkovo observatory,

visited Byor Castle in 1844 and 1850. He marveled at the

"enormous accumulation of light at the focus" and the details

which could be discerned, although noting that the image precision left something to be desired. He also concluded that

such an instrument would only be second-rate for the Pulkovo

observatory.,
wherein our ancestors displayed great energy and skill, were

impossible without astronomical. knowledge. In 1690 at

Kholmogory on the Northern pvina, near Arkhangei'sk, Russia'

first astronomical observatory is founded by A. A. Lyubi.mov

(the archbishop of Kholmogory) to meet the needs of navigatio

of the pomors.

Peter 1, who did much to advance science and the arts i

Russia, was also interested in astronomy. During his Europea

journey he visited observatories of Greenwich and Copenha

and after returning to Moscow in 1701 lie organized a "school

for the ingenius arts of mathematics and navigation" in the

fortress of Sukharev. An astronomical observatory was instal

in one of the upper stories of the Sukharev fortress, and

astronomy was taught at the navigation school.

In 1725 the Astronomical. Observatory of the St. Petersbu

Academ^, ,k+_ Sciences was set up in three stories of the tower

Academy of Sciences building on Vasi1'yev island (at

preseiit the Kunstkamera building). M. V. Lomonosov played a

tremendous part in furtherance of geographical explorations a

the development of astronomy in Russia. In 1762 he designed

and built his own reflector telescope, and initiated many geo

graphical expeditions to chart the territory of Russia, sometimes to the most remote corners. Under the charge of S. Ya.

Rumovskiy, director of the Petersburg Observatory in 1763-180

geographical expeditions were organized to compile Russia's

first "Catalogue of Astronomical Coordinates" of geographical

sites.

In the early XIX century, other observatories were

founded in Russia: the naval observatory of Nikolayev,

university observatories at Vil'no and Lerpt (now Tartu). In

1831 Moscow observatory was built.

10
The founding of Pulkovo observatory. By the early XXX

century it was clear that the Petersburg observatory could no

longer assure the requisite accuracy and required workload.

The construction of another large observatory was seriously

debated. This was built from the designs of its founder and

first direotor V. Xa. Struve, previously director of the

astronomical observatory of Derpt. The reputation of Struve

was earned by predicting the development of astronomy, selectin

or designing such instruments, choosing such collaborators,

and organizing the observations in such manner that in no more

than 30 years after its foundiag Pulkovo observatory became

famous as the "astronomical capital of the world".

The site of the observatory was chosen in the Pulkovo

hills (75 m above sea level), 19 km south of the center of 

St. Petersburg. And even though the infelicitous location of

the observatory (proximity to a large city, bright summer night

was apparent to its founders, it was realized that the Pulkovo

hills are the most convenient site in the district. The observatory building was designed by the architect A. P. Bryullov,

brother of the artist K. P. Bryullov. The architecture of the

building stressed the astronomical function of the structure.

It was oriented from east to west, with the main facade facing

north, to the city. It consists of three towers with domes in

which the telescopes are lodged. The main instruments are

installed in meridian rooms, joining the central tower to the 

eastern and western. 

Two-story buildings with living quarters and laboratories

have been added onto the observatory at the east and west. To

the north of the observatory toward the city runs a straight 

highway, oriented along the center of the observatory a;id

directed due north, as thoucrh a physical embodiment of the 

"Pulkovo meridian". The observatory was situated in 

park. Trees shadowed the buildings and produced an improved

astronomical microclimate.
Rational design and clearly specified function, dictated

by Struve, are a characteristic feature of the astronomical

instruments of 'Pulkovo observatory. 1 This helped, place the

observatory at the head of all the rest. The work of several

generations of Pulkovo astronomers resulted in the renowned

Pulkovo catalogues of fundamental stars, whose positions are

determined w:.th highest accuracy. These catalogues formed the

basis of all subsequent fundamental catalogues and were much

more reliable and accurate than those of Greenwich, Leipzig

or Leyden.

The Pulkovo instrument fleet was continually expanded and

improved. The Pulkovo astronomers jealously watched for any 

new astronomical instrument novelty. As soon as a new generation of refractors appeared, the largest in the world. was

instantly commissioned at Pulkovo, a 76-cm (30") refractor,

A installed in 1885. In 1893 the observatory obtained a so-call

normal astrograph, inaugurating the age of precision photograp

w observations. Even in the period of Soviet power the observat

was equipped with a large solar spectrograph (1924) and severa

years later with a wide-angle zone astrograph, used to compile

a photographic catalogue of northern stars down to the 11-th

magnitude in the zone of declination from +70 1 to the North

Pole.

{'41

Affiliates of Pulkovo observatory were successfully

developed in the south of the USSR - at Nikolayev and Simeiz.

But we shall return to the later history of Pulkovo 

^

y

somewhat below.

iWe can give a striking example. Two instruments of Pulkovo

observatory -- a large transit instrument and .large vertical 

circle (naturally modernized and furnished with modern radiation receivers and (spectrometers?] - still operate today, 

no less accurate than the similar modern instrume

than 140 years of uninterrupted good service is an ex

a "lifetime" for a technical instrument or machine?
Astronomical instruments

Frinci2al characteristics of the telescope. it is only

possible to study distant celestial objects by one method -

rollecting and anal;, zing their emission. It is precisely for

this purpose that the telescope is used. We shall mainly dis

cuss the classical, optical telescopes, which gather rays in

the optical range. But specialized telescopes exist for worki

with ultraviolet and infrared rays, radio, gamma, and X-rays.

Usually when we speak of an optical telescope we are

referring to its optical section. But in order to gather ligh

the telescope must also be pointed at a given site of the

f

sky and the given bearing maintained throughout the observa-

^ tion. For this we need an appropriate PP riate mechanical structure p

and mechanisms for fast and precision tracking, as the astrono

call them. The structure should be rigid, so the mutual arran

, merit of the optical parts is not affected, while the motion i

i should be smooth and uniform, to prevent image jerking in the

field of vision. Such a mechanical structure with motion

mechanisms is known as the telescope mount. Finally, the

collected light must be received and analyzed, using radintion

receivers.

Whatever the optical layout of the telescope, it is

characterized by several principal parameters. The first of 

these is the diameter of the entry aperture D: for lens telescopes this is the diameter of the free aperture of the objet- 

tive lenses, while for mirror types it is the diameter of the 

main telescope mirror. The larger D, the more light the telescope can gather. Indeed, it is often designated by the

The telescope can only be formed from all three elements

together. They should all be of identical high quality. If

one of them is poor the whole telescope will be worthless.
w

x

diameter of the inlet aperture: the 65-cm large astrograph

of the Pulkovo observatory (the modern one - the older one 

76-cm), the 2-m reflector of Shemakhinsk observatory, the

5-m reflector of the Mount Palomar observatory, and the wor

largest 6-m Soviet telescope.

The distances to the stars, as compared with the dimen

of man and his :instruments, are so large that they can be ta

as infinite, and the penc?1 of beams leaving them as parall

Such a pencil of lightbeams, arriving at the main telescope

mirror, is gathered into a point known as the main focus an

denoted F. The distance f from the apex of the main mirror 

the roint F is the focal distance of the main mirroro if t

telescope has additional optical elements (secondary mirror

lenses), we speak of the equivalent focal distance of the o

system f'. In other words, f' is the focal distance which w

obtain if the main mirror collected the incident beams at t

same angle as they are in fact gathered by all the optical 

ments jointly.

No optical system can be ideal. Distortions get into 

image from an actual optical system. These are generally t

aberrations of the optical system. Along the optical axis 

aberrations are negligible, but rapidly increase away from i

It is precisely the aberrations which restrict the field of

operation in the focal plane, where the images approach the

ideal and can be measured. The size of such field is known 

the visual field of the telescope and denoted 20.

Ordinarily a telescope's visual field is not large. Fo

the majority of reflectors it is 12-20' in diameter. Only 

the widest-angle astrographs does it reach 6 1 . Granted,

specialized short-focus cameras have a broader field, but th

short focus and certain other drawbacks render such cameras

unsuited to the majority of astronomical chores.

14

^,_ -
The ratio between the diameter and the focal distance A 

known as the relative aperture of the telescope. ) The potent

capabilities of a telescope are characterized by its penetrab

e:pressed by the brightness of the weakest object observable 

the given telescope. This depends on the lens diameter, but

also the manufacturing quality of the optics, the tranquility

and transparency of the atmosphere, the brightness of the bac

ground sky, the losses of light in the telescope optics, and

such factors not always strictly accountable. Therefore the

penetrability can only be approximated.

The penetrability differs for pointlike objects (stars)

and extended objects (various nebulae). For extended objects

the luminosity of the image is proportional to the aperture

a ratio, and the stronger the telescope the dimmer the nebulae

which it can pick up. The strongest telescopes used to obser

feeble nebulae have A = 1:2, 1:1.5 and even 1:1.

For stars which ideally give pointlike images, the image

area is not important, and the penetrability in this case is

expressed by the limit of the star magnitude accessible to th

telescope.

When D is increased; riot only does the stellar magnitude

limit increase, but also the resolution of the telescope is

improved, i.e. the capacity to distinguish two close and almo

merging stars.

1 Sometimes A is known as the telescope's aperture ratio, but

this is inexact. The aperture ratio is the amount of light

that a telescope can create in the focal mane. Disregarding

the losses of light in the optical system, the aperture ratio

is proportional to A . This is obvious, since the amount of

light collected by the telescope is proportional to the area

of the lens, i.e. the square of the diameter of the inlet

Opening D 2 , and is distributed over the image area, i.e. inve

to f2.
at the Mount Wilson observatory. Their mirrors were made of

glass, having a parabolic shape, while the relative apertures

are 1:4 or 1:5. Somewhat later, in 1917, a 2.5-m reflector

was built for the Mount Wilson observatory. In all, prior to 

1940 there were 12 reflectors built with diameter of 1 m or 

more, including the 1-m reflector started in construction at

Simeiz (USSR) in 1926. Reflectors are being constantly 

and today they have almost totally supplanted reflectors. 

The largest refractor, whose double lens objective has a 

diameter of 102 cm focal distance 19 m and A = 1:19, was 

installed at Yerkes observatory, USA in. 1897. Today refractor

are no longer being built with objectives whose diameter is

larger than 65 cm.

Refractors, reflectors and mirror-lens telescopes. Tele

scopes are divided by optical layout into refractors, whose

optical system consists solely of lenses, reflectors, includin

only optical mirror elements, and combined mirror-lens systems

otherwise known as catadioptric telescopes. The choice of a

particular optical layout depends on the problems confronting

the observer.

In the past century, for many decades refractors possesse

considerable advantages. They produced the best image, had th

broadest visual field and, especially important, their image

quality did not depend on the direction of the telescope tube.

But even by the end of the last century refractors had reached 5

the limit of their capabilities. )

Lens objectivf,, s are more 

expensive than mirror types, and hard to manufacture. The len

is fastened in a mount only about its perimeter, and therefore

large lenses begin to buckle under their own weight when the

telescope is tilted (leading to increased aberration).

f

The development of astrophysics, on its part, requires 

ever more powerful telescopes with ever greater penetrability.

As far back as the turn of the XIX century, huge reflectors

were created: the 90-cm at Licks observatory and the 1.5-m
The most simple optical layout of a reflector has one mai

mirror, gathering beams at a main focus, where a receiver is

placed. The basic optical layouts are shown in rig. 2, althou

others also exist, about which we shall also say something.

The Cassegrain layout was developed into the Ritchie-Chretien

. But in this layout the main and secondary mirrors have complicated shape, as a rule hyperbolic. This complex shape substantially enlarges the field of good images, attaining 1° at

diameter. Along with the advantages, reflectors have certain

drawbacks, mainly occasioned by mirror aberrations.

Mirror-lens optical systems, or catadioptric telescopes,

form a separate class of telescopes with lenses serving to

j correct the aberrations intrinsic to the main mirror. In this

case the lenses are known as lens compensators. The use of

compensators can increase the aperture ratio and visual field

of the telescope, and sometimes enables a shorter telescope

tube. The most common mirror-lens telescope systems are those

of Schmidt and Maksutov.

In 1932 B. Schmidt published a description of his own

telescope, in which a correction pens of complicated shape was

mounted at a distance equaling twice the focal distance in a

pencil of parallel beams arriving on the main mirror. This

corrected practically all aberrations of the main mirror and

enabled a powerful wide-angle instrument. A certain drawback

of the telescopes of -the Schmidt system (as well as the

Maksutov) is the fact that their focal field is not planar,

but spherical. As a consequence, either the photographic

plate must be bent into spherical form, or an extra correction 

lens must be mounted in front of the plate, rectifying the 

field but restricting its dimensions. 

The largest telescope of the Schmidt system is installed

at the Tautenburg observatory (GDR). It has a correction lens 
rd

()RI ►1NAL F-AGE 13

OF POOR QUAMY,

. F

d^

Y' 4 e^ ^ .^ Q t

,z

r

t

Fig. 2. Optical layouts of telescopes: a

refractor telescope; 4-lens objective (1)

collects a parallel pencil of beams in the

focal plane (2) where a receiver of radiation

(photographic plate) is placed; b - reflector

telescope; parallel pencil of beams is incident

on the main mirror (3) and gathered at the

main focus (4), where a radiation receiver

(usually photographic plate) is placed;

c - Cassegrain layout; a parallel pencil of

beams reflected from the main mirror (5)

arrives at the secondary convex mirror (6),

is reversed, passing through the aperture (7)

at the center of the main mirror, and collected

at the 'focus of Cassegrain" where is a receiver

of radiation (PEM-optoelectronic transducer,

spectrograph camera or photographic plate)

(8); d - k.ude layout; a convergent pencil of

beams reflected from a secondary convex mirror

is led outside the telescope tube (across the

poly axis) by means of plane mirrors (10,11)

and collected at the kude focus (12), where

is an immovable receiver (13) of radiation

1.8
(usually a spectrograph camera with high

dispersion); e - mirror.-lens system of

Schmidt; a parallel pencil of beams passing

through a correction plate (14) is reflected

from the main mirror (15) and gathered on a

curved focal surface (16), where there is a

photographic plate; f - system of Maksutov;

a parallel pencil of beams refracted by the

meniscus (16) is slightly enlarged and

reflected from the main mirror (17) and the

secondary convex mirror (18), and is collected at the Cassegrain focus (19), where

a radiation receiver (photographic plate) is

mounted. In front of the focal plane is a

field rectifying correction lens (20).

diameter 1.37 cm, a main mirror diameter 2 m, A = 1:3, a visu

field 5°. The second largest is the "Large Schmidt" telescop

installed at the Mount Palomar observatory, whose correction

lens diameter is 122 cm, main mirror diameter 183 cm, A = 1:2

and visual field 6.6°. This instrument was used to produce a

detailed sky atlas, known as the Palomar survey, which contai

r stars down to stellar magnitude +21.1. 

The famous Soviet optician D. D. Maksutov proposed, in 

order to correct for aberrations of the main mirror (not a

parabolic, but simply a spherical mirror), that a concavoconv

lens (meniscus) be mounted close to the main focus. A menisc

telescope is characterized by simple optical fabrication (sin

all the surfaces are spherical) and a shorter tube than the

similar version of the Schmidt system. Such telescopes have

i

i been installed in several observatories of our country. They 

are produced by the Leningrad Optics and Mechanics Union (LOM

The largest telescope of the Maksutov system is installed at

the Abastumani observatory. It has a meniscus diameter of

70 cm, a main mirror diameter of 100 cm, A = 1:3 and visual

field 41501.

,; 

Telescope mountings. Have you ever had occasion to look

' at a star through powerful binoculars? If so, then you know 

a 
i"

that the star does not stand still, but trembles continually.

No matter how strong and firm your arms holding the binocular

to your eyes, they always shake slightly and the star describ

an intricate broken line in the visual field. This is not s

noticeable when viewing ground objects, as the observer's

attention is absorbed in the opening panorama, while a star

is a point, and this point travels continually across a dark

field. Therefore, when observing the stars we must place the

binoculars on some kind of stand.

For this very reason a telescope also needs a stand. Of

course, the matter is more complex, for a telescope weighs

hundreds of kilograms, or more likely many tons. Moreover,

such a stand should allow the telescope to be aimed at the

most diverse points of the sky, and maintaining a given telescope bearing with high precision. For its part, the Earth

continuously revolves on its axis, which is manifested in the

daily motion of the stars across the sky. Consequently, the

stand should also compensate for this daily motion of the sta

maintaining the telescope's direction in space with an accura

down to hundredths of an angular second.

Thus, the telescope stand has a rather complicated struc

ture and is known as the telescope mount. This is placed on 

massive iron column and consists of two axes, corresponding t

the two axes of spatial coordinates, and has a clockwork move

ment mechanism. The mount may be extremely diverse in struct

although a number of its elements have the same function. 

A telescope weighs hundreds of kilograms, sometimes even

many tons, and yet its motion should be smooth, with minimum

friction. Such motion is achieved if the given system turns 

with respect to the center of p gravity. Therefore the telesco

tube is secured to the axle in a way that balances the objective and ocular ends. When the tube is arranged at one end o

20
d) ej

a) b)

OF POOR QUALITY

the axle, a counterweight is placed

of the moving parts (tube, axle and

is equalized relative to the common

though this increases the weight of

above the weight of the tuba, all tJ

ment are greatly facilitated, and a

ficient to turn a many ton machine.

at the other. The weight

counterweight), in turn,

center of turn. And even

the mount by nearly 4 tame

ie movements of the instrusmall synchro motor is suf

The simplest is an azimuth mount, corresponding to an

azimuth system of coordinates (Fig. 3a). One of its axes is

vertical , , the other horizontal. Such a mount is used for smal

theodolites and certain astronomical instruments. This mount

is troublesome in that, to compensate for the daily revolution

of the Earth, the tube of the instrument must be turned simultaneously about the horizontal and the vertical axes, at different speed.

P '•PPP

Fig. 3. Telescope mounts: a azimuth with vertical and 

horizontal axles.. b -parallax (equatorial), with polar

axis and declination axis, German type (with straight 

column); c - parallax, German type, with broken column;

d - parallax, English type; e - parallax, fork type;

t - triaxial for satellite cameras.

21
This defect is eliminated by a 2arallax (or ecguatoxial)

mount (Fig. 3b), having a polar axis (parallel t o the axis o

revolution of the Earth) and a declination axis, perpendicul

to this. After the telescope is positioned along the declin

tion axis and aimed at a star, the instrument need only be

turned about the polar axis by using a clockwork mechanism a

constant speed, corresponding to the speed of the Earth's

revolution.

For small telescopes a parallax mount with straight

column is most common. This mount is usually called the

German mount: last century it was often used by designers o

German companies. But if the telescope tube is long, and th

column is tall, then the tube will brush against the column 

certain positions (of. Fig. 3b), resulting in mechanical

damage to the telescope and, in addition, in1possibility of

viewing certain sky regions. In this case the column is tilt

and its upper part is used as a sleeve for the polar axle. 

result is a German mount with broken column (Fig. 3c).

Another version of the parallax mount is the so-called

English mount (Fig. 3d). This has a polar axle resting on t

supports: northern (top) and southern (bottom). The polar

axle is longer t.nd more firm.

Powerful telescopes, mainly reflectors with diameter of

1 m or more, are extremely heavy. An effort is made to light

the structure of their mount by making it symmetrical, with

no counterweight. Such, for example, is the fork mount

(Fig. 3e). The polar axle of this terminates in a bifurcatio

between the two arms of which the telescope is aligned along

the center of the short declination axle. In this mount, th

fork must be very massive, to increase the rigidity.

More complicated mounts are used in telescopes for obser

vation of artificial Earth satellites. Besides the usual tw

22
axles (vertical and horizontal, or polar and deolination), the

also have a third axle, directed at the pole of orbit of the

satellite (Fief. 3f) . This is called in fact the orbital axle

The telescope turret. The telescope and its auxiliary

systems are installed in a special building - the turret, pro

tecting it against wind and rain. Many of the past observato

were accommodated either in small separate pavilions or simply

in a room if there was a large enough window or opening hatch

And even today for simplicity we sometimes resort to such li'rh

weight pavilions for small instruments. At any rate, the tele

scope is placed on a stable, firm foundation, and the temperat

in the room where the telescope is installed should equal the

outer air temperature, to avoid air currents around the telescope, r8sulting in dicker of the images of the observed star

These conditions specify the form of the astronomical turret

(Fig. 4) .

In the center of the turret is a massive pillar, the base

of the telescope. The pillar is embedded in the ground and

rests either on a rock foundation or on bedrock. A column is

set up on this, as well as the particular telescope mount,

elevated by the pillar so that the telescope has a free vantag

in all directions of the horizon. The walls of the turret are

embedded in the ground to the same depth as the pillar beneath

the telescope. This is done so that microse,ismic vibrations

or shaking of the soil by passing transportation vehicles are

shielded by the walls of the turret and do not reach the telescope pillar. As a rule, the turret has a round shape. It is

just such symmetrical structure which best accords with unifor

temperature distribution in all parts of the turret. Inside

the turret, at a level allowing the telescope to sight on the

zenith, and allowing the observer to conveniently approach the

telescope eyepiece, is the floor of the turret. To prevent the

shocks produced by the steps of the observer from reaching the
ORICI,141 1. rAGE M

OF po()R QUALO,

Fig_ 4. A telescope turret: 1. - telescope;

2 - stone pillar, base of telescope; 3 - walls

of turret; 4 - revolving dome; 5 - opening

hatch of dome; 6 roller track for the

revolving dome; 7 movable cart for the

observer; 8 and 9 power supply and control

equipment for the turret and the telescope;

10 - ventilation ducts.

telescope and causing the image to shake, the floor of the

turret rests against:-the walls and is nowhere in contact with

either the pillar or the telescope column.

when the telescope is aimed at a star near the horizon,

it is quite difficult for the observer, to reach the eyepiece. 

Therefore either a portabjk. stairway rolling over the floor of

the turret or a special lift cart is provided in the turret.

A rising floor is installed in the turrets of long-focus

refractors.

To avoid air turbulence and other undesirable temperatnr

effects, natural and artificial ventilation is installed in th
turrets. The dome of large telescopes has two layers, with an

air flushing between the outer and inner cladding, and heat

insulating cushions between these. The largest telescopes are

lodged in turrets with air conditioning units. At the outside

the turret is often clad in metal louvers, protecting the ston

walls of the turret from direct heating by the Sun. The turre

is painted in either shiny aluminum or white, taking up the

least heat radiation. The best paint is considered to be

titanium white, with good reflection of visible and infrared.

And in good time before the observations it is mandatory to

open the hatches of the turret and air it out. In small turrets, 40--60 min are sufficient; for larger ones, at least 2 h.

But the turret of the 6-m reflector of BTA is constantly air

conditioned at the temperature of the outside air.

Light receivers. The role of the telescope is to gather

the incident radiation from the object of observation. The

gathered light must be registered and analyzed: determination

of the direction of the incoming light and its composition,

i.e. the physical nature of the emitting object. All of these

including the diverse characteristics of the radiation, are

recorded and analyzed by means of radiation receivers. All of

these are based on either the direct action of light quanta

on the recording medium or the interaction between quanta and

a photocathode, which forms an interim electronic image.

The First receiver of light was the human eye. Laborator

research has established that, for a visual perception to aris

it is necessary for about 33 light quanta per 0.1 s to arrive

at the necessary spot at the base of the eye. However the eye

is not a very sensitive or precise receiver of light. The

most widely used light receiver is a 2hotographic emulsion,

either in the form of photographic plates or films. Plates

better convey the correspondence between the various parts of

the image and are easier to store over time . But the photo- .

25

Nw
graphic laboratories are not always able tQ cast the necessa

varieties of photoemulsion on glass, and therefore it is oft

7 necessary to use wide-format films.

. It is assumed that a photographic plate of 35 x 35 cm 

' about 2.10 $ light-sensitive grains, i.e. some 2 . 10 3 individu

elementary receivers of radiation, and each in addition with

appreciable gradation of darkne,s density. Thus the photoemulsion has remained the most useful receiver of light.

Experience shows that 9 out of 10 light quanta incident

on a photoemulsion are reflected or transmitted by it, and o

one quantum hits a light-sensitive grain. To form a nucleu

the latent image, made visible after developing, it is neces

for about 10 quanta of light to hit the sensitive grain. Th

" to form a single nucleus of the latent image requires 100 li

quanta, i.e, the photoemulsion has a l% quantuni efficiency.

tt

But even so the quantum efficiency of photoemulsions do

not suit the astronomers, and they are seeking ways o

the sensitivity. Processes of hypersensitization of the pho

emulsion make use of direct pre-heating or flushing of the

plates in a stream of nitrogen or hydrogen.

Photographic portraits of the sky are further convenien

in their ease of storage. The older observatories have "gla

4 

Libraries" - repositories of sky photographs gathered over

many decades of observation. They hold tens of thousands of 

b

negatives. The importance of such information stores is har

to overvalue.

Heat receivers absorb the incident radiation and conver

' it to heat. They include bolometers, whose electric 

{ increases upon heating (sensitivity down to 10 -14 W); thermo

Ccells, in which the heating of a junction of two heterogeneo

26

;s

yf .
0

metals produces an electromotive force (sensitivity down to

10 -10 W); heat radiometers, acoustic or pneumatic detectors,

whose sensitivity matches that of the best thermocells, althou

they work in a longer wave spectral region. The heat receive

employed in the infrared portion of the spectrum also include

liquid crystals, which change color upon heating.

A television receiver consists of a television transmitt

tube, mounted at the telesvope focus, as well as video amplif

power supply, regulators, a communication channel and a receiv

television tube or kinescope. The transmitter tube resolve~ t

image into rows, and the rows into elements (video signals),

which are amplified by the video amplifier, sent to the labora

and either form an image on the kinescope screen by means of a

sweep layout, or are recorded on magnetic tape, or are put in

computer. A television monitor is convenient because the

illumination intensity in the image is amplified on the kinescope by 10 5 -10 8 times in relation to the image brightness at

the telescope focus. But for determining the mutual position

and brightness of the objects of the observation, it is less

accurate than the usual methods.

Photoelectric light receivers are fused on the photoeffec

when light is incident on a metal cathode, electrons are emitt

in the direction of the positively-charged electrode (and may 

accelerated and focused by electromagnetic field). This produ

a photocurrent, proportional to the amount of incident light.

Photoelectric receivers are extremely diverse in layout. They

include both photocells, and photomultipliers (PEM), anc, photo

resistors, and photodicdes, and image converter tubes (ICT).

The most common have become the PEM and ICT.

When roughly 50-100 light quanta hit a PEM, a single

photoelectron is formed and then accelerated and turned into

a stream of electrons, photographically recorded by the observ
28

or stored in computer. The light quanta arriving at the cathu

of an ICT knock out photoelectrons which are focused by magnet

or electrostatic field and sent to the screen of the ICT with

large magnification (on the order of 10 4 -10 7 ), forming a magni

fied image of the observed object. The screen dimensions of

good ICT have a diameter of about 40 mm and a resolution on th

order of 40 lines per mm. Excellent results can be had by

combining an ICT with backup recording equipment of television

type or computer input.

A new type of ICT are the microchannel plates, consisting

of a large number of fine tubes of poor-conducting glass. A

photoelectron knocked out by light quanta is accelerated by

electric field, hits the wall of the tube and knocks out

secondary electrons, which in turn trigger a full scale avalanche at the output of the tube, thus creating a magnified

image. Each such tube is a sort of solitary image, and the

signal from it is recorded by photoemulsion, on a phosphor

screen, or sent to computer. Such elementary radiation receiv

can even be superior to photography, but only when recordinc

images of low information content. They work well in those

cases when images are studied that contain, no morE, than

1000 elements. Chiefly, these are spectra. But they are

greatly inferior to photography in observing broad fields with

large number of stars.1

A detailed discussion on radiation receivers can be found

in the special literature, e.g. the astrophysics textbooks. W

1There are also electron c ameras, in which photoelectrons act

directly on an emul i on of photographic plates, being a sort s

of photographic ICT. The sensitivity is raised by roughly 10

times over ordinary photography, but both the photocathode and

the photoemulsion should be in a vacuum, The difficulty here

is that the photoemulsioi adsorbs atmospheric gases prior to

loading in the camera ani once inside these gases are released

ruining the vacuum and "poisoning" the photocathode.

e
OF POOR QUALITY

shall only add that the designs of the receivers are au$te

diverse and improvements are rapid. While telescopes as

ti

opticomechanical machines survive for several decades (the

average "lifetime" of a telescope is considered to he 50 years

radiation receivers displace each other every 5 years,

Observational conditions. Astroclimate. Astronomers

are far from indifferent to the climatic conditions under whic

the observatory functions. Foremost in desirability is a

maximum number of clear nights and minimum number of cloudy. 

Of course, if a cloudy night becomes clear for even 2 h, the

astronomers will use this "window" and observe; as they say,

a meteorologically cloudy night has become astror?tinically clea

It is obvious that there are much more astronomically clear

than meteorologically clear nights. For example, for Pulkovo

and Moscow the number of astronomically clear nights is from

70 to 100 per year, whereas the number of meteorologically

clear (Table 1) is 32 and 30, respectively.

Table 1. Relation between meteorologically clear (N ) and

overcast (N ) nights for several sites in the USSR m 

(after the Rata of P. V. Shcheglov)

Stations 11m No Stations N N

in o

Pulkovo 32 177 Abastumani

Moscow 30 162 Alma-Ata 66

Crimea 78 108 Tashkent 142 W

Lower Arkhyz 83 121 ` Sanglok 128 99

Byu,rak:an Maydanak

145 80

But it is not enough to the astronomical observer for 

the sky to be free from clouds. It is further needed that

it be free from haze, dust, with high transparency, untroubled 

star images, and low background illumination of the sky. The 

entirety of these and certain other factors constitutes the

meaning of the astroclimate. For example, even if the number
of meteorologically clear nights is almost the maximum of 142

for Tashkent, the overall dust burden, poor transparency, and

high illumination make this place unfit for installation of

large telescopes.

In order to search for areas with optimal astroclimate,

special astronomical expeditions are outfitted. It has been

established that loan peaks of 1000-2000 m, sufficiently remo

from large cities and industrial complexes, in a locality wit

a large number of meteorologically clear nights, usually have

the best astroclimatic conditions. Today observatories are n

longer built near large cities. The aim is to move them to t

mountains, in localities with optimal astroclimate. Recently

the attention of astronomers has been drawn to the astroclima

conditions on the Canary and Hawaiian Islands and in the Sout

Hemisphere, in the foothills of the Cordilleras.

In the Soviet Union the mountain regions of the Crimea,

4

the Caucasus, Central Asia and Eastern Siberia come close to

such conditions. In exploring the astroclimate, Soviet astro

discovered two summits with exceptionally good astroclimate

characteristics: Sanglok in Tadzhikistan and Maydanak in 

Uzbekistan. They are recommended for construction of observatories with large telescopes.

Radiotelescopes. These are used to determine the bearin

Y of a radio source, the intensity and spectrum of its radio

emission, the structure of extended sources, and in making

radio surveys of the sky. The radiotelescope, as the optical 

t

telescope, consists of a radiation-gathering antenna, a

mechanical mount enabling the telescope to be aimed at the 

necessary segment of the celestial sphere, and a re

radio waves - a half-wave dipole (or horn), which receives

waves of the selected len

30

c

p
The antennas of radiotelescopes are structurally diverse

and gigantic in size. The form of the antenna is dictated by

the range of wavelengths received by the antenna. Cup-shaped

,parabolic antennas with diameter of several dozen meters are

established on azimuth mounts and can be directed to any port

of the visible hemisphere of the sky. The action of such

antennas is analogous to that of a reflector telescope. Such

for example, is the RT--22 radiotelescope of the Crimean

astrophysical,. observatory in the Goluboy gulf, near Simeiz,

and the similar radiotelescope at Pushchino, near Moscow. Th

parabolic antennas have diameters of 22 m and receive in the

shortwave range. The largest radiotelescope of such type in

the Soviet Union, the RT-70, has a parabolic antenna of 70 m

diameter.

Larger radiotelescopes have fan-shaped antennas, consist

of a large number of individual reflecting mirrors, each controlled by its own mount and sending the incident radiation to

a single common feed, which summates the radiation reflected

by the group of such mirror reflectors. Such is the largest

radiotelescope in the Soviet Union, RATAN-600, which shall be

discussed more closely afterwards.

The antennas of large-size radiotelescopes are often

fixed or limited in mobility. Changing the region of sky fro

which radio waves are received is done by repositioning the

feed. The largest antennas used to receive long-wave radiatio

are constructed. in the form of lattices of elementary receiver

dipoles or vibrators.

One drawback of radiotelescopes is the relatively low

resolution. To enhance the resolution, radiointerferometers

are used. These consist of two or more antennas, working in

the same range of wavelengths, observing the same source at

the same time, but separated by a distance known as the base

3
of the radiointerferoineter. This differs for the various

radiointerferometers: from several meters to several thousan

kilometers. In the latter case we talk of radiointerferomete

with superlong base.

r, Depending on the length and direction of the base,

radiointerferometers may attain a resolution down to 0.001"

in ascertaining the dimensions and positional coordinates of 

source, i.e. more accurate than optical astronomy.

Astronomical Observatories of the USSR

The func tion of observatories. The gathering of diversi

fied observational material collected with the large telescop

,a

built in the late XIX to early XX century (mainly reflectors)

enabled astronomers to understand the structure of the Galaxy

1

determine the position of the solar system in it, and [`]

r` determine the place of the Galaxy in the Universe. [However X( 2

the power] G of the telescopes built-in the first half of the

XX century aid not suffice to penetrate far into the Metagala

So it was until the middle XX century. The explosive develop

ment of physics in the postwar period, especially nuclear

physics ai( the physics of elementary particles, provided a 

new and mighty stimulus to the development of astrophysics

(astrophysics itself became a sort of experimental laboratory 

r for nuclear physics). There was increased penetration of 

g = physical methods and methods of modern computer technology

into astronomical investigations. And astronomical observatories became major scientific research organizations, numbering dozens or even hundreds of scientific personnel.

Modern astronomical observatories not only possess a sto

of observational instruments, but also laboratories for prol Illegible text.

+ 2original almost illegible.

32
cessing and storage of the observational material, specialized

metrology, computation and optical laboratories. It is mandatory for observatories to have well-equipped workshops, where

new and unique (not mass produced) instruments and auxiliary

apparatus are built. Practically all observatories have their

z° own computer centers with one or more computer. And all of

4

this influences the present mission of certain astronomical

observatories, emphasizing their special significance as

scientific institutions.

Perhaps the reader knows that the Pulkovo observatory is

officially known as the Chief Astronomical Observatory of the

USSR Academy of Sciences (GAO AN SSSR). But the observatory

of Tashkent, with a history of more than a century, is today

known as the Astronomical Institute of the Uzbek Academy of

Sciences, the Observatory of Dushanbe is known as the Institut

of Astrophysics of the Tadzhik Academy of Sciences, and so on:

And these are essentially authentic scientific institutes, wit

E a numerous staff, diverse laboratories, workshops, garages and

administrative office. But since the source of astronomical

knowledge is still observation (optical, radioastronomical

I and exo-atmospheric), all these institutes are generally speak

observatories.)

A--tronomical observatories differ in the subjects they

study, their instrument outfit, and even the number of workers

1The single exception is the Institute of Theoretical Astronom

of the USSR AS (ITA) in Leningrad. The ITA is involved in

calculating the ephemerides of the stars, Sun and planet,

publishing the "Astronomical Annual of the USSR" for the curre

and subsequent years - the major reference aid, containing

exact positions of the stars, planets, Moon and Sun, data on

rising and setting, eclipses, etc. Besides the "Astronomical

Annual of the USSR", the ITA figures out and publishes

"Tables of Star Cover by the Moon", the "Ephemerides of the

Small Planets", and other tables needed by specialists.

3
The largest are administered by the Academy of Sciences of the

USSR or the academies of science of the Union republics. Such

for example, are the Chief Astronomical Observatory of the

Ukrainian AS, situated in the Goloseyevo forest near Kiev, or

the Shemakhinsk astrophysical observatory of the Az AS, having

one of the largest telescopes in the USSR, a 2-m reflector.

Several solar or radioastronomical observatories belong to

research institutes of adjacent fields: the solar observatorie

of the Institute of Earth Magnetism and Propagation of Radio

Waves of the USSR AS (IZMIRAN) at Vatutinki near Moscow and

the Institute of Earth Magnetism and Propagation of Radio

Waves of the Siberian Division of the USSR AS (SiblZMIRAN)

in the Eastern Sayan.

Fifteen universities of the USSR have their own astronomical observatories, handling both academic and scientific

problems. Among them are such major observatories as the

State Astronomical Institute im. Shternberg (GAISH) at Moscow

State University im. Loironosov, celebrating its 150th anniversary in 1981, and the astronomical observatory of Leningrad

State University im. Zhdanov, which became 100 years old in 

1980. The observatories of Kharkov, Kazan', Kiev, Odessa,

Ural (at Sverdlovsk), Riga, and several other universities

are well known.

The conditions of observation at the older observatories

near large cities are deteriorating continually. Thus new

observatories are built in the mountains, away f

population centers, in areas with optimal astroclimate. Such

sire Abastumani observatory in Georgia, Byurakan observatory

in Armenia, Gissar observatory in Tadzhikistan. The older 

observatories are constructing observation bases in such

territories: Pulkovo in the mountains near. Kislovodsk and

at Ordubad, in Southern Azerbaydzhan, the GAISH in the Crimea 

and near Alma-Ata, the GAO AN USSR at Terskol in the Caucasus,

etc.

34
There are now a total of about 50 scientific observatories

functioning in the Soviet Union (Table 2) •• academic, universit

and gcVornmental. This number includes the branch divisions -

the observational bases and stations. Furthermore, a number of 

observatories exist at the planetariums, pedagogical institutes

and the Ala. Union Astronomy and Geodesy Union (VAGO), which

brings together amateur astronomers. These observatories are

used for cultural, academic or amateur purposes.

Table 2. Main astronomical observatories of the USSRI

Name Date of

Foundatio

Abastumani astrophysical observatory of the

GRUZ. AS

Astrophysical institute of the Kaz. AS

(Alma-Ata observatory)

Ashkhabad astrophysical laboratory of the TURK. AS

Blagoveshchensk latitude station of the GhO AN SSSR

Byurakan astrophysical observatory of the Arm. AS

Solar observatory IZMIRAN at Vatutinki (near Moscow)

Vil'nyuss astronomical observatory of Vil'nyuss

State U. im. Kapsukas

Gissar astronomical observatory of the Tadzh. AS

Chief astronomical observatory of the USSR AS

(GAO AN SSSR) at Pulkovo

1932

1942

(1950)

1946

1959

1946

1960

1753

(1926)

1963

1839 

(1ri54)

1944 

1932

(1958) 

Chief astronomical observatory of the Uk. AS

(GAO AN USSR) at Goloseyevo

Institute of astrophysics of the Tadzh. AS

(Dushanbe observatory)

In parentheses are the dates of modification or reorganization
Table 2. Cont'd.

Name bate 

Foundat

Zvenigorod observational station of the Star

Council of the USSR AS 19

Special astrophysics observatory of the USSR AS

(SAO) near Zelenchuk 196

Radioastronomy station NIRFI at Zimenki, near

Gor'kiv 196

Astronomica'observatory im. Fngel'gardt at Kazan'

State U. im. Ul'yanov-Lenin 190

Kazan' municipal astronomical observatory of

Kazan' State U. im. U1'yanov-Lenin 181

Astronomical observatory of Kiev State U. im.

Shevchenko 184

Kitab international latitude station im. Ulugbek 193

Kis,lovodsk solar station of the GAO AN SSSR 194

Crimean astrophysical observatory of the USSR AS

(KrAO) 195

Southern observations base of the GAISH in the

Crimea 195

Kourov astronomical observatory of Ural State U.

im. Gor'kiy 196

Astronomical observatory of Leningrad State U.

im. Zhdanov 188

Astronomical observatory of Lvov State U. 190

r,

State astronomical institute im. Shternberg (GAZSH) (1931

at Moscow State U. im. Lomonosov (Moscow Observatory) 1954

b ^

Nikolayev branch of the GAO AN SSSR (Nikolayev 182

astronomical observatory) (191

Astronomical observatory of Odessa State U. im.

Mechni}ov 1

Poltava gravimetric observatory of the Ukr. AS 192

Radioastronomical observatory of the FLAN at Pushchino 195

z; 36

., ..: ,

M ....^1^"'"+".. r. .r.•

4 ... iiu.c.,
Table 2. Cont' d.

Name Date 

Founda

Raga astronomical observatory of the Latvian

State U. im. Stuchka 192

Riga astrophysical observatory of the Latv. AS 196

Samarkand astronomical observatory (museum) 4V 

Simeiz experimental station of the Star Council 190

of the USSR AS (197

Ta;;tu astronomical observatory im. Struve of the 180

B. AS (196

Astronomical institute of the Uzb. AS

(Tashkep t astronomical, observatory) 187

Uzhgorod observational station for satellites 195

Ussuri solar station SiblZMIRAN 195

Astronomical, observatory of Khar r kov State U. im.

Gor'kiy 180

Shemakhinsk astrophysical observatory of the Az.

AS 195

The special astrophysical observatory (SAO). In the

foothills of the Northern Caucasus, south of Cherkessk, where

the forest-covered mountains become the magnificent summits

of the Main Caucasian range, is located the Special Astrophys

Observatory of the USSR Academy of Sciences (SAO). If the

observatory had been named after the locality, it might have

been the Zelenchuk observatory, since the nearest populated 

point is the station of Zelenchuk. However it is differently

named, for it has two gigantic instruments - the world's larg

optical telescope BTA and the immense radiotelescope RATAN-60

Alongside the laboratory building of the SAO have been 

constructed workshops, garages and residential buildings. Al
are situated in a shady picturesque gorge on the bank of the

swift mountain stream Bol l shoy Zelenchuk and are known as the

settlement of Nizhniy Arkhyz, to distinguish it from Verkhniy

'x Arkhyz, a village in existence for several decades upstream.

But the local inhabitants, as well as the astronomers themselves, affectionately call their settlement Bukovka or Bmkovo

after the beeches growing on the slopes of the surrounding

mountains. The exterior of the village has almost nothing to

,t

w suggest the astronomical specialization of this institution.

r Only on the laboratory building are there two tiny turrets

I; with small auxiliary telescopes. And it is even hard to see

the stars from within the gorge. Yet precisely here, at

Nizhniy Arkhyz, is the center of that scientific complex form

f ' by the SAO. From here, astronomers sally forth to make obser

vations with the BTA. It is here where they work on the

acquired data and make preparations for further observation.

^

0M^

i 

BTA - Large Telescope Azimuthal. Following the highway

above Nizhniy Arkhyz, after 19 winding turns of the mountain

road (and the highway is splendid here), the observers reach 

one of the summits of the foothills - the natural Landmark of

a. Semi Rodnikov (Seven Springs]. Here, at a height of 2070 m, i 

is the world's largest optical telescope with main mirror

diameter of 6.05 m. It is known as the "Large Azimuth Telescope", or BTA. The USSR Academy of Sciences created a specia

committee to allocate the work time at the BTA, consisting of

>g 

representatives of the SAO and all the major observatories of 

the Soviet Union. This committee gathers and reviews request

^^

from Soviet and foreign observatories and individual astronom

`- It evaluates the significance and urgency of the requested 

programs. Visiting astronomers, including foreigners, are

allotted 70% of the observation time, the SAO workers 30%. 

The design project of this giant telescope was begun by

a group of Pulkovo observatory, headed by the prominent optic

1S

38
and designer D. D. Maksutov. Later, after his death, the

work on this telescope: was conducted by another leader of the

Soviet optico-mechanical industry, Lenin prize winner B. K.

loannisiani. Involved in the project were a group of engineer

and designers of the Leningrad Optics and Mechanical. Union,

(LOMO) and many outstanding astronomers and O ticians of the

USSR.

The LOMO was the main builder of the BTA. But a whole

series of factories and institutes of the USSR, including

such major ones as the Kirov and Admiralty factories of Leningrad, took part in biI lding the giant telescope. The glass

blank for the mirror was cast at the optical glass factory of

Lytkarino, near Moscow. An aluminum plating plant for the

mirror was set up at Gor'kiy. Other factories of Moscow,

Rostov on the Don, and other cities also participated. In

token of this, at the approach to the BTA on the last segment

of the road there is a sign: to Moscow 1890 km, to Leningrad

2620 km, to Rostov on the Don 540 km, to Gor'kiy 2190 km.

The preparatory work and installation of the necessary

equipment alone took about three years. The molten glass

body was transported along a gas-heated discharge chute and

then along a platinum pipe, heated by hydrogen flame, to a

mold for annealing and slow cooling. Two blanks were cast.

The first of these, used for pilot production, was cooled

rather fast - it was thought to require nixie months for coolie°a.q

The blank did not stand such a cooling rate - °-he homogeneity

of the body was disturbed, and it split into two roughly equal

parts (which were used to manufacture auxiliary focusing

...Irrors)

The second or main blank, on the basis of the former

experience, was cooled more slowly, at a rate of 0.03 K/h.

Its cooling lasted for 2 years and 19 days. The resulting

3
blank was first subjected to roughing to impart the given shap

which took 16.5 months and 15,000 carats of diamond tool. In

the course of the machining, the weight of the blank was

reduced by roughly 30 t. Later a third blank was cast.

In the polishing shop - a room with firm foundation and

triple heat insulation - were inst4lled a polishing machine an

apparatus for studying the mirror. Only two people worked in

the room - the breathing of a third would have altered the

temperature conditions of the slop. In final form the mirror 

is 650 mm thick, 6050 mm in diameter, being a meniscus with

surface of curvature radii equaling 48 m and, consequently,

focal distance of 24 m. In its lower portion there are 60 roun

depressions to hold the relief bearings, situated in four concentric circles. A calculation shows that the relief system

can preserve the surface shape of the mirror so that the defor

mations do not exceed 1/16 the wavelength of light.

The mirror was ready in June 1974, its final weight being

42 t. The mount of the mirror was made at the Admiralty facto

of Leningrad. Shipping the mirror, like any other major telescope parts, was an unique transportation job. They were ship

by water, along the Volga and the Don to Rostov on the Don.

Here powerful tractors hooked up to the platforms with the

telescGpe parts and slowly, carefully hauled them to the

mountains. It was summer and hot, the cargo was heavy, the

asphalt melted beneath the tractor wheels. Thus, traveling

along with them were road-building machines, continually

sprinkling the platforms and the tractor wheels with water.

They proceeded in this way for two days and 530 km to the

station of Zelenchuk. After this, the mountainous segment

of the highway began; the tractor rigs with trailers painstaki

climbed the steep turns of the road.

The de;ign of the mount of the BTA was a complete novelty

in the astronomical practice of the world. To appreciate the

40
full complexity of the affair, let us recall that the second

largest telescope in the world after the BTA, Mount Palomar,

has a mirror diameter of 5 m, which is 1 m smaller than the B

The weight of the Mount Palomar mirror is 13 t, while its mov

parts weigh about 500 t. How many times should the weight of

the moving parts of the BTA be increased if its mirror weighs

42 t7

After considering various versions it was recognized tha

a large parallax mount would be very heavy, massive, and awkw

in the engineering sense. It was proposed to use an alt-azim

mount, one axis vertical, the other horizontal, with the instr

ment turning about these axes through the azimuth and the alt

tude. With such a mount, in order for the telescope to follow

a star, the instrument must be turned about both axes simultaneously, through different angles of turn at different speed

Naturally, this is inconvenient. As far back as the XVIII ce

' tury such mounting was rejected. l

But that which was difficu

and impractical in the XIX became the only acceptable solution

4

in the ,latter half of the XX century.

The alt-azimuth mount is perfectly symmetrical. When

turned about the vertical (azimuth) axis, the load on the

vertical axis remains constant and evenly distributed. Tilti

and buckling of the telescope tube occur only in one plane and

depend solely on the altitude of the observed point. T.ae mir

relief system is simplified, as is the balancing of the tele- 

scope. All of this simplifies and lightens the structure.

The negative aspects of the alt-azimuth mount - simultaneous

j motion about two axes, nonuniform speeds of these motions, and 

l Incidentally, the very word "alt-azimuth" is treated by certain authors as "old-azimuth", deriving it from the German

alt - "old". But in actuality the word comes from the Latin

altum - "altitude", and the name of the mount should be understood as "altitude and azimuth".

-^

_.. .• 
rotation of the visual field - were able to be mastered by

using a control computer and sufficiently fine movement

mechanisms.

By using the alt-azimuth mount the weight of the moving

parts of the BTA is 850 t, which is no more than 1.6 times

larger than that of the Mount p alcmar telescope. The manufacturing precision of the BTA assemblies (and it consists of

25,000 designated parts) and the finness of balance of the

overall telescope are such that the movement of this apparatus

is achieved by a motor of no more than 200 W.

Fig. 5 shows the layout of the BTA. It consists of a

vertical support axis, carrying a horizontal platform of 12 m

diameter, on which there rest two vertical columns 8 m high.

At the top of the columns are the bearings of the hor7zontal

axis, 2.2 m in diameter. At the outside of the columns, horizontal platforms for observers are secured. The vertical axis

rests by its spherical surface (6.6 m in diameter), polished

by the same machine as the main mirror, on six concave polishe

spherical bearings of the same radius. The entire weight of

the telescope rests on these. In the gap between the spherica

surface and the bearings, oil is supplied under high pressure,

forming an intermediate film several hundredths of a millimete

thick. The several tons of bulk of the telescope float on thi

film of oil, as on a hydrostatic bearing.

The BTA can operate by two optical systems: at the major

(primary) focus and in a Nesmith layout. At the primary focus

the light losses are smallest, although the visual field free

of aberration is no more than 2'. To enlarge the visual field

a two-lens compensator is placed in front of the main focus,

augmenting the field to 13 1 . When observing at the main focus

the observer is in a special cabin known as the cup, with the

major focus located just within this cup. Since the cabin is

in the path of the pencil of beams incident on the main mirror

and the heat of the astronomer's own body in the cabin disturb

42
f

OF POOR QUAMY

Fig. 5. Layout of the BTA: 1. - bearings

dictating the direction of the horizontal

axis; 2 - vertical columns carrying the

horizontal axis and side observation

platforms; 3 - main horizontal platform;

4 - vertical axis; 5 - ball. bearing of

vertical axis; 6 - hydrostatic bearings;

7 - base bearing and regulator of the direction of the vertical axis; 8 - gearing for

turning the telescope about the vertical

axis; 9 - ruin mirror; 10 - `cup" in which

the observer is found when observing at the

major focus; also lodges the lens correction

system or a secondary convex mirror for observati(:as by the Nesmith system; 11 - plane

4
mirror to direct the rays within the horizontal axis onto the observation platforms;

12 - side observation platforms on which

fixed radiation receivers are placed.

the temperature field of the telescope, the cabin is enclosed

at all sides after the observer gets in. The walls of the

cabin at the inside have a heat insulating cover, and a ventilation system is supplied to the cabin to assure the necessary

exchange of air for the observer.

The Nesmith system includes a secondary convex mirror,

mounted in the lower portion of the cup to replace the lens

correction system. The secondary mirror sends the beams back,

where they encounter a small plane mirror in their path, which

sends the; rays to one of the observation platforms holding the

reception equipment. In this layout the BTA has a focal distance of 180 m and relative aperture 1:30.

Studies by BTA observers revealed that its image quality

is rather high: 61% of the light is concentrated in a spot of

0.5" diameter and 91% in a spot of 1". This indicates that th

image quality is mainly governed by the tranquility of the

atmosphere, and not the quality of the mirror. The new telescope enables observation of the stars by direct photography

methods down to a stellar magnitude of 24.5, or 25 under

specially favorable atmospheric conditions.

A special tower was constructed for the BTA telescope.

We can get an idea of its .size by noting that the distance

from the main mirror to the cup where the primary focus is

situated is in excess of 24 m (Fig. 6). The dome of the tower

weighs about 1000 t, its diameter along the rolling circle is

44.2 m, and the working area of space beneath the dome is

3536 m2 . The entire volume beneath the dome should have an

identical temperature equal to the outer air. Thus the BTA

44
dome should be comprised of three layers of Duralvmin panels

with heat insulating liners. Not far from the BTA tower,

just a little downhill, a ventilation plant has been built

with a powerful air conditioner, capable of supplying air of

identical temperature as the outside to the space beneath the

dome year-round. This air is forced inside the cladding of the

dome and aerates the space beneath the floor of the tower.

The hatch of the tower opens to a width of 11 m. It is

covered by a visor, which is thrown across to the opposite

side of the dome during the time of observations. The weight

of this visor is 33 t.

The complicated control mechanisms of the BTA requires at

night during observations the presence, besides the observer

in the cup, of a team of engineers and attending personnel to

monitor the working of the telescope mechanisms: It is therefore clear that every minute of use of the telescope is extreme

valuable, and the work time should be strictly rational in use.

It remains to add that, since the opening of the BTA in

1977, interest scientific results have already been gathered,

although it exceeds our subject to discuss them. The 

mounting proved to be extremely successful. It will evidently

form a part of practical telescope design for much time. Eve

now an English reflector, of 4.2 m diameter is being built on a 

similar alt-azimuth mount, to be installed on the island of 

La Palma in the Canaries, and a telescope of 7.6 m diameter is 

being designed for Texas University i n the USA.

The radiotelescope RATAN-600. Forty km to the north of

Nizhniy Arkhyz, at the outskirts of Zelenchuk station, the

largest radiotelescope in the USSR has been built, with a total

antenna surface of more than 13,000 m2. The diameter of the

ring antenna is 600 m. This radioastronomical telescope of 

45
is

,

Fig. 6. Arrangement of the BTA in its

towers

the USSR Academy of Sciences (hence its acronym RATAN-600) beg

service in February 1977. It is part of the SAO, but in contrast with the BTU, is located not on a mountain, but rather in

a valley encircled by a gentle bend of the Caucasian foothills

The antenna of the RATAN-600 telescope is a reflector

ring in the form of a wall of 895 rectangular, aluminum mirrors

each 2 m wide and 7.4 m tall. At the rear of each mirror ther

are 276 bearings, securing it to a metal girder. These bearin

can move. They turn the mirror, move it forwards or retract i

regulate the shape, imparting the necessary concavity. In thi

way, the mirror buckling caused by temperature changes or the 

cumulative effect of internal stresses is compensated. Each •

girder is mounted on a massive ferroconcrete base, 

stable mirror fixation. To use most fully the capabilities 

of the radiotelescope it is necessary for all 895 mirrors to

function in coordination. This can only be done by using a

control computer, altering the setting of all the mirrors in

synchronization.
OF POOR

The radio emission gathered by the reflector antenna is

sent to the feeds. These are in the form of mobile laborator

which can travel along rails. A receiving antenna, or second

feed, is mounted on the roof of each of the three such cars.

This receives the radiation collected by the many mirrors of

the antenna and reflects it to the primary feed - a horn, whi

is the input of the reception and mensuration equipment.

Depending on the altitude angle of the observed region, the

feed must be positioned at various points of the field (Fig. 7

For this, inside the ring formed by the antenna there are rai

tracks along which the feed cars can from place to pla

assuming the most rational position.

6

Fig. 7. Diagram of the RATAN-600 radiotelescope:

1 - laboratory buildings; 2 - reflector ring;

3 - straight feed; 4 - rails for movement of

feeds; 5 - feed cars; 6 - radio receiver;

7 - turntable.

Strictly speaking, RATAN-600 is an azimuth telescope. I
can register the emission from a radio source passing through

a given meridian or azimuth. The design of the radiotelescope

enables observation of radio sources in the zone of declinatio

from -40 to +90 0 , i.e. roughly 70% of the total surface of the

celestial globe, In principle, it is possible to aim all 895

mirrors of the antenna at a single point of the sky, close to

the zenith. But usually the RATAN-600 telescope is controlled

so that, when the mirrors of one side of the ring are aimed at

one point of the sky, the mirrors of the other part receive

emission from another portion of sky. Thus, RATAN-600 can

observe three regions of the sky in three different azimuth

directions. Roughly a quarter of the telescope mirrors functi

in each of these.

The dimensions of the collecting surface of the antenna 

mirrors determine the quantity of received radiation. The

effective area of the mirrors of each particular part of the 

radiotelescope amounts to several thousand square meters.

RATAN-600 can receive radio emission with wavelengths of 8 mm. 

to 30 cm. The information collected in the course of the observation is processed by computer, practically at the same

time as the observations themselves. When the radio source

passes through the azimuth of the feed, the computer figures

out and prints its coordinates, intensity, and other 

and transcribes this data into the memory of the machine, for

later use in more complete processing.

Observations with the radiotelescope are almost indepen

dent of atmospheric conditions. The large area of the reflect

antenna and use of a special procedure dispenses with weather 

constraints, enabling observation both in cloudy weather and 

during the day.

Pulkovo observatory at the present day. From the 

first days of World War II, Pulkovo observatory was subjected 

48
to fierce bombardment and artillery barrage. The enemy was not

allowed to enter the territory of the observatory, but for more

than 900 days the front passed in the immediate vicinity thereo

All its buildings were destroyed. The large 76-cm refractor.,

the normal astrograph, the horizontal solar telescope, and the

major portion of the unique library were lost (only the objective lenses of the first two surviving). only several medium

sized instruments were saved, moved to Leningrad and stored in

the basement of the Academy of Sciences building.

On 11 March 1945, when the war was s 6(Lill on, the decision

was made to restore and expand Pulkovo observatory as the

Chief Astronomical Observatory of the USSR. Academy of Sciences

(GAO A14 SSSR). The observatory was restored to its classical

form, as the massive stone foundations embedded in the ground

and carrying the instruments before the war had been almost

untouched, and it was possible to replace some meridian instruments in their former position. But prior to rebuilding the

observatory, it was necessary to clear out the territory and

its surroundings from mines and unexploded 

In 1947, when the reconstruction was in full swing,

Professor A. A. Mikhaylov (member of the USSR AS since 1964) 

was nominated director of Pulkovo observatory. In the same

year the first postwar astronomical observations were done with

two instruments. The opening celebration of the restored

Pulkovo observatory was held in 1954.

There is no sense in describing here all the telescopes

of Pulkovo observatory. The meridian instruments were complete

restored and even increased in number - new Soviet-manufactured 

instruments were created. The main building stands on the same 

foundations as before, while the center of the circular hall 

of the central tower continues to be the starting point of the

Pulkovo meridian - the starting point of all astronomical-geodet

triangulation networks of the USSR. At present astronomical 

49
50

r .

observations on wide-ranging scientific subjects are being co

ducted at Pulkovo. But in addition to the independent observ

tions, the GAO AN SSSR is examining and working on astrometri

catalogues obtained from other observatories around the world

A Soviet branch of the Center for Astronomical Data is in exi

tence at Pulkovo, working on analysis and dissemination of

astrometrical data in the USSR and abroad.

Pulkovo has an active latitude facility and time facilit

For these, new instruments have been introduced: the ZTL- 180

zenith telescope, small transit instruments with photoelectri

registration, and others. Great attention is paid to determining the fundamental constants of astronomy - the constants

of precession, nutation, and aberration. On the suggestion o

Mikhaylov, a polar tube was built - a fixed instrument for

photographing a region of sky near the North Pole. Using this

regular observations have been carried out for more than a

quarter century to determine these constants. Using modern 

knowledge as to the structure of the atmosphere as a basis,

the famous Pulkovo tables of refraction have been updated and

are getting ready for a new, fifth edI tion.

Regular photographic observations are carried out to

determine the natural motions of the stars, to study the move

ment of the larger planets and their satellites, the small

planets, binary stars, stars with dark (invisible) satellites

and other interesting objects. For this purpose, the normal 

astrograph has been restored and a new long-focus astrograph 

(65 cm in diameter, with focal distance 10.5 m) has been

installed. The members of the observatory built a new and 

original structure of horizontal meridian circle of the L.. A. 

Sukha.rev system.

The physics of the Sun and a solar study facility have 

an important place in the projects of the GAO AN SSSR. These;
are directed by corresponding member of the USSR AS, V. A. Kr

The observations are being done by a newly-built horizontal

solar telescope and other devices. A considerable portion of

the Sun observations is being done at the Mountain Astronomic

Station near Kislovodsk. Pulkovo is one of three Internationa

Centers (USSR, USA and France) gathering all observations of

the Sun and publishing a monthly bulletin "Sun Data". 

At the GAO AN SSSR a, division of radioastronomy has been

organized. For this, a laboratory building has been construc

on the south slope of Pulkovo hill, and alongside there are

several radiotelescopes, including a fan type of 90 reflector

mirrors, situated along an arc of a paraboloid with chord dia

meter 120 m. At the focus of the paraboloid is a feed, conne

by cable to the receiving equipment in the laboratory building

Observations are conducted at the meridian, while for altitud

aiming the tilt of the reflector mirrors is appropriately

altered and the feed is moved. The Pulkovo radiotel.escope

served as prototype for the already-described RATAN-600 radio

telescope.

Speaking of the GAO AN SSSR, we cannot fail to mention i

department of astronomical instrument design, managed by D. D

Maksutov until his death in 1964. In this department, new

astronomical instruments are being designed and built, both

for the observatory itself, and for its branches and expeditio

while the members of the department develop recommendations an

take part in the creation of many of the major telescopes of

the USSR, including the BTA and RATAN-600.

As already noted, due to the proximity of a large city,

as well as the bright nights, the conditions for observation

at Pulkovo are far from ideal. Therefore the Pulkovo astronom

are trying to move their instruments to the south, in the

mountains, where the astroclimate is better. For astrometric

^ 3 .ai .,,ter- - • Jw• . w - '. - ,, 
52

-ON

observations at the marine observatory of Nikolayev, the Nikol

division of the GAO AN SSSR has been created. In fact, this 

a major modern observatory, specializing in astrometrical stud

As at Pulkovo, it has a -i_qe transit instrument, a vertical

circle, a Repsold meridian circle (commissioned as early as

V. Ya. Struve for the Pulkovo observatory, and transferred to

ti

Nikolayev after the war), a photographic zone astrograph,

instruments for a standard time service, and several others.

^. The Nikolayev observations are important supplements to Pulkov

and have been recognized internationally.

To study the revolution of the Earth, a latitude station

has been constructed at Blagoveshchensk on the Amur, separated

by approximately 90 0 longitude from Pulkovo. The ZTL-180 zeni

telescope built by the LOMO is installed here. In the mountai

of Transcaucasia, near Ordubad (Nakhichevanskaya Associated

i Republic), a permanent expedition of Pulkovo observatory is

i

in operation, furnished T. th instruments for photographing

the starry sky.. On the mountain Shat Zhad Mas t 28 km from

Kislovodsk, at a height of 2070 Ai, in a locality with astroc1,i.mate favorable to solar observations (as many as 337 observation days per yearly, the Mountain Astronomical Station of

i

the GAO AN SSSR has been built.

It is precisely in the mountains, where the scattered

light is less and the sky is darker, that observation of the

solar corona is facilitated. At the Mountain Astronomical

Station of the GAO AN SSSR, a photoheliograph of the Maksutov

system, a chromospheric-photospheric telescope, used to photograph the solar disk in the Ha line and to make observations

of the solar corona, two eclipse--outside coronographs, includi

the world's largest with an objective diameter of 53 cm (focal 

1Gnevyshev, M. N., "The Mountain Astronomical Station"

Vselennaya, 3, 1979, p. 50.
;2

M

H

distance 8 m), and other instruments, in particular a

two-component radiointerferometer and two small radiotolescope

have been installed.

The complex of instruments at the Mountain Astronomical

Station renders possibl y: observations of the Sun in the radio

and optical ranges simultaneously. Since the radio emission

of different wavelengths comes from different layers of the

solar atmosphere, whereas optical facilities enable observatio

of the photosphere, the chromosphere, the protuberances and th

corona, the observations at the Mountain Astronomical Station

simultaneously cover the phenomena in all layers of the solar

atmosphere. The work of this station is directed by M. N.

Ghevyshev.

The Crimean Astrophysical Observatory of the USSR AS (KrAO

As far back as the end of the past century the inconvenience

involved in observations at observatories close to large citie

had become apparent, and the issue was debated of creating a

new observatory in the south of the USSR. The site was chosen

in the Crimea on the mountain Koshka, just above the resort of

Simeiz. In 1908 a dual_ astrograph was built there with objectives 12 cm in diameter and a branch of Pulkovo observatory wa

opened. Regular observations of the small planets and variabl

stars were begun with this instrument.

After the October Revolution, Simeiz observatory began to

expand quickly. The number of scientists increased: in 1925

G. A. Shayn and his wife P. F. Shayn arrived at the observator

During this same time, Soviet diplomats, especially L. S. Kras

managed to fill orders for scientific equipment from the

capitalist nations, requisitioned by the Academy of Sciences

from before the revolution, and new agreements were made.

Among the other equipment from England there arrived a

102-cm telescope, the largest reflector of that time in the

USSR. Under the direction of G. A. Shayn, it was installed

53
at the Simeiz observatory. This reflector was equipped with 

spectrograph, which was used to begin the study of the physic

nature of stars, their chemical composition and the processes

which take place in them.

 

' In 1932 the observatory obtained a photoheliograph for

zz photographing the Sun. Several years later a spectroheliosco

,s was installed to study the surface of the Sun in the line of

a certain chemical element. In this way, Simeiz observatory

became involved in major work to study the Sun.

The modern instruments, up-to-date scientific subjects,

and enthusiasm of the scientists made the Simeiz observatory 

the leading astrophysical observatory of the USSR. But the

} war began, and the observatory suffered great loss. Its

^r

buildings were burned, the laboratory equipment destroyed or

evacuated. In retreating, the fascists shot up the main mirro

of the 102-cm reflector with automatic weapons.

Y 

In 1945 a decision was made to restore Simeiz observatory

and to situate it in a different more appropriate spot, with

respect to astroclimate, and also to change it from a branch o

Pulkovo observatory to an independent organization - the Crime

Astrophysical observatory of the USSR Academy of Sciences

(KrAO). After a series of astroclimatic studies, a new site 

was selected for the observatory in the mountains, 12 km to 

the east of Bakhchisaray (a, little more than 30 km by highway)

a bit further away from the heavily-lit cities of the southern

shore of the Crimea - Sevastopol' and Simferopol'. Here, on 

small. flat elevation at a height of 600 m above sea level, 

construction began on the observatory and a scientif

ment, the so-called Scientific Village. 

At the new observatory a broad front of astrophysical 

research was developed, continuing and elaborating the work 

54
begun at Simeiz. 1 The Crimean Astrophysical Observatory

received a numerous stock of first-class instruments. The

first to be installed was a 40-cm dual. astrograph, used for

diversified astrometric and star-astronomical observations,

but mainly search and discovery of small planets and comets.

Moreover, replacing that lost in the war was a Ze.Lss reflector

with mirror diameter 122 cm. This was used to continue the

studies of physical processes in the atmospheres of stars,

begun as far back as Simeiz. A 63-cm wide-aperture camera,

a 50--cm telescope of the Maksutov system, an eclipse-outside

coronograph and a number of other telescopes were installed.

Somewhat later, in 1954, a turret solar telescope (BST)

was placed in service, equipped with diversified receiving

gear for studying the spectra of the surface of the Sun. To

investigate more closely the influence of the Sun on processes

in the atmosphere of Earth, an instrument complex_ was created

for studying the atmosphere and ionosphere and for registering

changes in the Earth's magnetic field.

In 1952, A. B. Severnyy became director of the KrAO

(member of the USSR AS since 1968). On his initiative, the

BST was built. In the 1970s, the BST was modernized. Thus,

new mirrors of sitall were installed: the 120 cm diameter

coelostat mirror, an additional 110 em diameter plane mirror

and a 100 cm diameter main concave mirror. The mirrors were

fabricated in the optical workshops of the KrAO. The resolution of the BST w--s increased: it is now possible to distinguish details of 0.3", which corresponds to 200 km on the

surface of the Sun. It was necessary to raise -the tower of

the BST by 10 m: after the reconstruction its height was 25 m.

1 A the site of the old observatory of Simeiz there has now

been opened up the Simeiz Experimental Station of the

Astronomical Council of the USSR AS, furnished with five small

instruments for observing artificial Earth satellites. A new

reflector with mirror. diameter 1 m is being installed at the

station.

55
In 1961 a mirror telescope in honor of G. A. Shayn (ZTSH

with mirror 2.6 m in diameter, made by the LOMO union, was

installed at the observatory. At that time, this was the

largest telescope in the USSR and in Europe. And even today, 

along with the 6-m telescope of the BTA and another 2.6 -m

telescope of the Byurakan observatory, it belongs to a trio o

the largest telescopes of the USSR, for which the observation

time is allocated by a special committee of the USSR Academy

of Sciences.

Radioastronomy has been developed at the KrAO, especiall

through study of the radio emission of the Sun, conducted

jointly with optical observations at the BST. A large radiotelescope has been built, its site chosen on the shore of the

Black Sea in the Goluboy gulf, to the west of Mount Koshka.

South of the observation platform is the open sea (where

radio interference is less); to the north, east and west the

platform is shielded by the Crimean mountains. It is here th

the RT-22 large radiotelescope has been set up, with paraboli

antenna in the form of s cup, 22 m in diameter, on an azimuth 

mounting. In contrast with the RATAN-600 radiotelescope and

the large Pulkovo radiotelescope, the RT-22 can be aimed at

any point of the sky with a control computer and can track th

object of observation for a lengthy time (aiming precision

about 15").

The RT-22 radiotelescope has become a powerful means of

radioastronomic research. It often works in tandem with the 

RT-22 radiotelescope of identical design and size at Pushchin

near Moscow. These together, form a radiointerferometer with 

superlong base, having a resolution of radioastronomic observations down to 0.002" at a wavelength of 1.55 cm. 

",t the KrAO, regular searches for small planets and

determination of their position are continued by tradition.

56
This work is directed by N. S. Chernykh. Each year, more than

2000 positions of various small planets are determined. In th

decade from 1965 through 1974 alone there were 35 new planetoi

discovered at the KrAO, each given a name and number. The

share of the observatory in such discoveries is about 40% of

the total of planetoids discovered in the entire world. A

comet has also been discovered here, named the Smirnova-Cherny

in honor of its discoverers. 

The State Astronomy Institute im. Shternberg (GAISH). In

Moscow, in the Lenin mountains not far from the altitude build

of MGU in the depth of a shady park is a 3-story structure wit

four astronomy towers on the roof. Scattered nearby in the

park are nine turrets and pavilions for various astronomical

instruments. This is in fact the GAISH - the astronomical

observatory of Moscow State University im. Lomonosov.

The Moscow observatory was built in 1831 in the outskirts

of Moscow in the region of Presnya. In the early XX centu.-y,

this was a rather well-furnished astronomical institution with

meridian circle, long-focus astrograph, wide-angle e

camera and several smaller instruments. At the observatory,

meridian and photography determinations of star positions,

search and study of variable stars, and investigation of

binary stars were carried out. 

From 1887 through 1920 P. K. Shternberg worked at the

observatory (director since 1916). He was a leading scientist

and revolutionary. In 1931, when three Moscow astronomical

institutions were combined at the Moscow observatory

was bestowed upon the unified astronomical institute, which

came to be called the State Astronomical Institute im. Shternb

(GAISH) .

In 1954, along with construction of the altitude building 

of MGU, a building complex was built for the GAISH; it receive

5
58

new instruments, the first large telescopes made after the

war by the optico-mechanical factory of Leningrad (now the

LOMO). In the Lenin mountains, a meridian circle, the ZTL-18

zenith telescope, the AFR-1 wide-angle astrograph (diameter

23 cm, focal distance 2.3 m), the AZT parabolic reflector

with mirror diameter 70 cm, a telescope of the Maksutov system

with meniscus diameter 50 cm and mirror diameter 70 cm, a

horizontal and a turret-type solar telescope, and a number of

other smaller instruments, as well as auxiliary equipment,

were set up.

At first the new building of the GAISH was on the outskir

of Moscow, but after the rapid growth of the city it was soon

surrounded by high buildings and broad, brightly-lit prospects

It became hard to conduct astrophysical observations, and as

far back as 1957 a permanent mountain station of the GAISH wa

organized at a height of 3000 m, 50 km from Alma-Ata, where

solar and spectral instruments were installed.

In 1958 in the Crimea the Southern Observation Station of 

the GAISH began to operate, located on the same summit as the

KrAO, near the village Prokhladnoye. The station is a

well-equipped astronomical observatory with 125-cm reflector,

made at the LOMO, two 60-cm reflectors from the nationalized 

enterprise Carl Zeiss Jena of the GDR, a meniscus Maksutov

telescope, and a 40-cm wide-angle astrograph, transferred

from Moscow.

In addition, the GAISH is constructing a new observations

base in the mountains of Central Asia at a height of 2500 m

on the mountain Maydanak, where the astroclimate is the best

in the USSR according to Moscow astronomers.

The GAISH is characterized by a close inter

between scientific work and the learning process at the
astronomy department of MGU. Three faculties work alongside

the science departments: astrophysics, stellar astronomy an

L;

astrometry, celestial mechanics and gravimetry. The directo

of the GAISH, Professor Ye. P. Aksenov, is also chief of the

astronomy department. The teachers of the astronomy departm

t, take pert in the scientific work of the institute, while the

scientists actively participate in the teaching process. Ea

m year the astronomy department graduates about 25 young astron

^s

Also studying here are roughly 30 graduate students, includin

f some from abroad.

r On the whole, the GAISH is a wide-ranging astronomical

institute, its projects covering almost all areas of modern

astronomy, from classical fundamental astrometry and celesti

;w mechanics to theoretical astrophysics and cosmology. In man

areas of science, such as exogalactic astronomy and the inve

gation of nonstationary objects and the structure of our

galaxy, the GAISH has one of the leading positions in the

USSR.

The Chief Astronomical Observatory of the U

during the war, in June 1944, a new structure of the Ukrainia

. Academy of Sciences was approved, where it was intended to

create the Chief Astronomical Observatory (GAO AN USSR). A 

place for it was set aside on the southern outskirts of Kiev

in the Golose,yevo forest, 5-6 km west of the Dnepr.. Around 

observatory there stretches a protective park zone more than

1 km in radius.

The main thrust of the activities of the observatory wa

3'! considered to be astrometry, although in time the GAO AN USS

became an institute with highly diversified concerns. Here

studies are conducted on the rotation of the Earth by method

of astrometry and space geodesy (the GAO AN USSR is the coor

dinating agency for the problem "Study of the Earth's Rotati
in the USSR) and work is done on fundamental and photographic

astronomy; the physics of the Sun and that of the Moon and

planets is studied. An important area is experimental astrophysics - the study of variable stars and novae, the physics

of galactic complexes. The director of the observatory since

1975 is corresponding member of the UkAS Ya. S. Yatskiv.

The observatory has a triple long-focus astrograph 1 , a

40-cm wide-angle astrograph, whose photographic field of visio

is 8 x 8 0 ; a large vertical circle; horizontal luni%r and solar

-telescopes; the AFR-2 chromosphere-photosphere telescope, the

70-cm AZT-2 reflector telescope, and a series of telescopes of

smaller size.

in 1970, construction was begun on the Mountain observati

Base of the GAO AN USSR, it was originally supposed to be

built in the Carpathians, but after a number of expeditions

exploring the astroclimate, with members of the GAISH taking

part, the site of the base was chosen to be a platform (3100 m

high) on the peak Terskol, not far from F1'brus. The astroclimate of Terskol is in no way inferior to that of the SAO,

while in atmospheric transparency and low relative humidity

is even superior. The conditions at Terskol are especially

favorable for observations in the infrared.

As early as 1971 the AZT-14 telescope (diameter 48 cm,

focal distance 7.5 m) was set up on Terskol for observations

of variable stars. Later the reflectors AT-40 (diameter 40 cm

and AT-80 (diameter 80 cm) with spectrophotometer for the near

1originally it had two objectives: a photographic 40 cm in

diameter with focal distance 5.5 m, enabling photographs of

the sky of 2.5 x 2.5°, and a somewhat smaller visual one. Lat

in 1970, the nationalized company Carl Zeiss Jena (GDR) built 

new photovisual objective, 38 cm in diameter with focal distan

5.5 m. All three objectives rest on a common mount.

60
infrared, built in cooperation with the astronomical observatory of Odessa University) and several telescopes of smaller

diameter were set up. The development of the observation

base at Terskol is increasing in pace. It is intended to

install a 2-m reflector of the nationalized company Carl Zeiss

Jena, a large horizontal solar telescope, a 1-m reflector,

and construction of a laboratory building and cableway.

As at other major observatories, a department of astronomical instrument construction exists at the GAO AN USSR. It

functions in cooperation with the astronomical observatory of

Odessa University. It is here where the reflectors AT-40 and

AT-80 were built. New reflectors of about 1 m diameter and a

number of astrophysical instruments, including the URAN-4

radiotelescope, consisting of 126 vibrators (it will be erecte

on the territory of Odessa .observatory) are being designed and

built.

In Kiev there is yet another astronomical observatory,

managed by Kiev University. it was founded in 1945, but a

discussion of it would exceed the bounds of our book.

The Abastumani Astrophysical Observatory. The Abastumani

Astrophysical Observatory of the Georgian Academy of Sciences

is situated 200 km west of Tbilisi on the picturesque spurs of

the Adzharo-Imeretinsk range, 10 km south of Zekarskiy pass,

on the mountain Kanobili (1650 m above sea level). It was

founded in 1932 through active cooperation of Leningrad

astronomers and was first located at the resort settlement of

Abastumani. Here photographic and photoelectric observations

of variable and binary stars were conducted. In 1937 the

observatory was moved up to the mountain of Kanobili, an area

distinguished by excellent astroclimate, with calm and transparent atmosphere. It became the first Soviet observatory

situated in the mountains. From the day of its foundation,

61
the scientific chief and director of the observatory has been

Ye. K. Kharadae, a specialist in the field of stellar &6trono

corresponding member of the USSR AS, and president of the

Georgian Academy of Sciences.

The first instrument at the observatory was a 33-cm

reflector - the first in Soviet optical instrument constructi

In 1937 a long-focus refractor (objective diameter 40 em,

focal distance 7 m) with two photographic cameras enabling

s'ky pictures with visual field 10 x 13 0 on 18 x 24 cm plates,

was installed at the observatory. The cameras have objective

prisms which can be used for pictures of star spectra. As of

1937, the 33-cm reflector has been working in combination wit

the first Soviet stellar electrophotometer.

In the postwar years, the observatory was greatly enlarg

and received new powerful telescopes. In 1955, a 70-cm telescope of the Maksutov system (meniscus diameter 70 cm, mirror

diameter 97.5 cm, focal distance 210 cm) was installed. The

telescope is furnished with an objective prism with d

angle of 8 0 ; this can produce spectra of stars down to the

13th magnitude.

In 1970 a 125-cm reflector specially designed for electr

photometric work with fully automated measurement processes

was installed at the observatory. The Latest addition to the

instrument arsenal of the observatory was a 40-cm dual astrograph of Carl Zeiss Jena. This is used for both stellar

astronomy and astrometrical determination of star and planeto

positions. 

The main research of the observatory is devoted to study 

of the structure of the Galaxy by classification of spectra,

color.imetry, and counting of stars in selected directions.

Studies are also conducted in the field of stellar.. dynamics,

r.

n,

w

t

^A f

f

^C
observation of variable and nonstationary stars. Extensive

catalogues of stellar quantities and parameters of the color,

spectra and luminosity of stars are being compiled at the

observatory. Broad use is made of the methods of electrophot

w metry and spectrophotometry. Several comets, planetoids and

hundreds of so-called emission stars have been discovered.

Systematic studies of the Sun have been conducted since 

the foundation of the observatory. For this, it is equipped

with a horizontal solar telescope, a photoheliograph and a

chromosphere -photosphere telescope. These instruments have a

large assortment of accessory equipment, including interferen

polarization filters. This instrument complex sustains a

regular solar service and study of active solar regions. Man

year studies of the upper atmospheric layers of Earth are als

carried out at the observatory.

The Byurakan Astrophysical Observatory. At Yerevan University since 1933 a modest academic astronomical observatory

has been in operation. In 1943 the Academy of Sciences of th

Armenian republic was organized, in which the Yerevan observa- 

forY was incorporated. p The scope of the scientific work of p 

the observatory is now almost entirely aimed at solving curre

problems of astrophysics. But the capabilities of the Yereva

observatory, situated within a major city, did not allow astr

physical observations. And as far back as 1944 the Academy o

Sciences proposed construction of a new astrophysical observatory. The creator of the observatory and its irreplaceable 

director is the member of the USSR AS, V. A. Ambartsumyan,

president of the Armenian Academy of Sciences.

The search began for locations with favorable atmospheri

conditions. Naturally the astronomers looked to the mountain

where 35 km from Yerevan on the southern slope of the mountain

Aragats near the village of Byurakan (about 1500 m altitude) i
1946 construction of the future observatory began. After the

village, the observatory became known as the Byurakan

Astrophysical observatory.

In its first years the observatory obtained several smal

telescopes. In 1954 the largest of these was installed - a

Schmidt telescope with correction lens and mirror diameter

r

53 cm and focal distance 1.8 m.

An important area of work of the new observatory came to

be the study of stars at equal stages of evolution. This are

was founded in 1917, when V. A. Ambartsumyan demonstrated tha

stellar associations contain relative young stars and are

centers of star formation. Observations of exploding stars

using a 53-cm Schmidt camera have proved to be extremely prolific. In general, the subject of research on exploding stars

as well as the so-called Herbig-Aro objects, became for many

years a major project of the observatory. While polarimetry

observations of stars led to the discovery in 1949 of natural

polarization of starlight.

In parallel. with the optical observations, beginning in

1951 radioastronomic research came to be developed. Using

two radiointerferometers, observations were made of discrete

radio sources at wavelengths 4.2 and 1.5 m. The receivers an

antennas for the radiotelescopes were built in the laboratory

of the observatory. Methods were developed for accumulating

weak radio signals, allowing a considerable increase in the

penetrability of the radiotelescopes. As a result, it became

possible to observe such weak radio sources as had previously

been detected only with the largest radiotelescopes.

By 1956 construction of the first stage of the observatory was completed. The building complex of the observatory

a main laboratory building which also contained a conference

64
hall, library and admiAistrative quarters, observation towers

an inn for visiting astronomers - was designed by the archite

S. A. Safaryan. The buildings were constructed of rose tuff

and are maintained in the national style. The observatory was

officially opened on 19 September 1956.

k

Since then the instrument arsenal of the Byurakan obsert•

vatory has been amplified more than once. Radiotelescopes

`. allowing observation of radio sources in a broad range of wav

length have been built and put in service. Some of the radio

telescopes have been installed at the radioastronomy base of

Saravande (above the village of Byurakan). in 1960 the large

Schmidt telescope in the USSR and one of the largest in the

^t world was pP ut in service r with a correction lens diameter of

1 m, equipped with three of the world's largest objective

prisms. The great penetrating range of this telescope, excel

image uualit;.y and large visual field conferred a primacy on t

Byurakan astronomers in a number of investigations of the

physics and morphology of the p gY ggalaxies. It was Proved that

trapezoid and chain type configurations prevail in galactic 

k systems. Observations supporting nonstationary phenomena in

exo-galactic objects have received special attention. Compac

blue galaxies with unusually strong ultraviolet emission have

been discovered. More than 100 objects of this class have

been found in observations with the Schmidt telescope of

Byurakan observatory.

In October 1976 an even larger telescope, with mirror

diameter 2.6 m, was put in service. It is an analog of the

ZTSH (and also built at the LOMO). This telescope is one of

the three largest telescopes of the USSR (along with the 6-m 

telescope of the SAO and the ZTSH -telescope of the KrAO). Th

observation time is allocated by a special committee of the

USSR Academy of Sciences.
Conclusion

The number of astronomical observatories both in the

world and in the U15PSR is constantly growing. Several of thes

have moved to a new situation with better observing condition

others have built themselves branches or observation bases.

The total n umber of astronomical scientific observatories in

the entire world (omitting amateurs) is currently in excess o

500, while 90% of these are in the Northern Hemisphere.

The nati4ral question is what will the telescopes of the

near future be like? What new design projects, what new concepts will be incorporated in astronomy, say, by the year 200

What will the astronomical observatories be like?

The telescope is an instrument with a long life. The

e xi sting telescopes have not yet used up their capacities.

It may therefore be supposed that the majority of large telescopes now operating will continue to do so in the year 2000,

although some of them may be moved to a new and more favorabl

site. Before the end of the century several more large telescopes will be built in tho USSR and new, improved radiation

receivers will be developed, with capabilities approaching

the theoretical limit.

New ways of using the telescopes are also intended, particularly deployment in outer space, beyond the limits of the

Earth's atmosphere, which will open broad prospects for

astronomical research. Projects are now in development for

%njecting into Earth orbit a 2-meteM optical telescope in

the mid-1980s, and it has been calculated that this will provide a gain of five stellar magnitudes over similar observations from Earth. Even so, the main areas of astronomical

observat.w.on outside the atmosphere will not be.optical, but

studies in the ultraviolet, X-ray and gamma ranges.

66
But space investigations will not fully replace terrestr

observations. Owing to their accessibility, simplicity and

proven .;;alities, ground optical observations will remain a

highly effective means of exploring the universe. Nor has th

developmen s, of terrestrial astronomical engineering reached 

itn limit. The construction of observatories in the mountain

in a locality with optimal astroclimate, enhznces the labor

productivity of the astronomers. There is talk of creating

in the early XXI century a telescope with mirror diameter of

20-25 m. Its total surface will be roughly 20 times larger t

that of the largest current telescopes.

It is not yet clear whether its mirror will be made of

a single block or a large number of individual mirrors - both

alternatives are under study. But it is more likely that

prior to this telescopes with diameter of 8-10 m will be: buil

A telescope project of Texas University has also been publish

with "superthin" mirror, 7.6 m in diameter and 10 cm thick, i

shape sustained by the action of numerous mechanical bearings

But it is considered more promising to build multi-mirro

telescopes. These are a set of 4, 6, 12 or larger number of

individual telescopes, each independently aimed at the object

of observation, and the information from each telescope is

summated in computer. Thus, even the 25-meter telescope can 

likewise be constituted (such alternatives are being examined

of 108 telescopes 2.4 m in diameter or 72 telescopes 3 m in 

diameter or 16 telescopes 6.25 m in diameter. Multi-m

telescopes, Dust as the so—called mosaic telescopes, are much 

cheaper and, most important, are easier to make than those of

identical size with mirrors of a single block of glass. The 

future apparently lies with these telescopes,
PN

ne

The Amateur Astronomer's Cornea ORIGINAL PAG2. 

F POOR QUAL('I"VEp How to Find a Star in the SX

in astronomy spherical coordinate systems are adopted to 

indicate the position of an object (such as a star) can the

celestial sphere. There are several such systems. Each is

specified by a reference plane and a point on the plane that

is the origin of coordinates. The system in fact is named af

the reference plane. When the reference plane is chosen to b

the ecliptic, it is an ecliptic coordinate system; when the

reference plane is the plane of the galaxy, it is a galactic

coordinate system, and so on. Most often the horizontal and

the equatorial systems are used.

global axis s .

,.

meridian

N it-^^^ ^ a. r r .. s

.^S`

°`

W

hOr^ on

^.• CiI'a e of

declinationE

a 2

yG

Major circles and points on the celestial

globe.

For the future discussion it is helpful to familiarize

oneself with several lines and points on the celestial sphere

The plane passing through the North Pole PN , the star E and

the South Pole P S forms on the celestial sphere the circle of

declinations of the given star. The circle of declinations,

68
OF POOR QUALi I f

passing through the poles of the globe, the zenith of the

observation spot z and the nadir point Na, is k n own as the

meridian (the meridian, of course, of the obse.^'r L-Jt t.on site,

since at each point on the surface of the Earth the direction

of a plumbline is unique). The meridian intersects the horizo

at two points - the north point N (closest to the North Pole)

and the opposite ( along the diameter) south point S. The poi

of east E and west W are equidistant along the horizon from

the points Nand S. in its daily motion, the star rises in

the eastern part of the horizon, crosses the meridian (culminates), then descends and sets in the western part of the

horizon.

Spherical coordinate systems:

azimuth Fystem - azimuth ,A and

height h, equatorial system -

right ascension a (or clock angle t)

and declination S.

On the celestial sphere there are many interesting and

important points associated with a particular celestial

phenomenon. We shall mention two more of these - the points

of intersection of the equator and the ecliptic. That point

where the Sun passes from the Southern to the Northern

Hemisphere is known as the point of spring equinox, or simply

the point of spring, and is denoted by the symbol for t'he

constellation Aries. The other is renown as the point of autumn

equinox, or the point of autumn, and is designated by the

C
symbol of Libra (shown in the figure),, These characters retai

their meaning, even though today the point of spring equinox i

now in the Crab constellation while the point of autumn equino

is in Virgo.

In a horizontal coordinate system the reference plane is

R the plane of the horizon, while the reference point is the

point of the south. One coordinate is counted uff along the

circle of altitude from the horizon to the star and designated

h. Another is counted off along the arc of the horizon from

the base of the circle of altitude to the point of the south.

It is known as the azimuth of the star and denoted by A. In

astronomy, the azimuth is counted from 0 to 360 0 , the count

gunning from the point of the south through the west. The 

horizontal system is convenient in that it clearly indicates

the position of the star on the vault of the sky. Knowing h

and A, the observer understands at once the conditions of

visibility in which the star is found: high or low above the 

horizon, in the north or south. But a drawback of this spheri

coordinate system is the fact that the coordinates change constantly from the daily revolution of the celestial sphere.

Therefore, in dealing with horizontal coordinates, it is

mandatory to specify the moment of time to which they refer.

The equatorial system of spherical coordinates is free

from this defect. Its reference plane is the plane of the

celestial equator, while the major point on it is the point

of spring equinox. One coordinate is counted off along the

circle of declination, from the equator to the star. This is 

the declination 6. It is counted off from 0 to +90 0 to the

North Pole and from 0 to -90 0 to the South. The second coordinate, or right ascension a, is counted off along the arc of

the equator from the point of spring equinox to the base of 

the circle of declination, counterclockwise from 

or from 0 to 24 h (in units of time). The right ascension

70
and declination are almost independent of time, uniquely

characterizing the position of the given object among the

stars, but have little to say as to the conditions of visibil

on the vault of the sky at a given time.

The coordinates of the stars vary little in time. In 

fact, there are only two reasons for change in these coordina

the natural motion of the star and certain phenomena connecte

with change in the coordinate grid on the celestial sphere.

The latter is mainly due to precession and nutation of the

Earth's axis, resulting in change in position of the poles

and points of spring and autumn equinox. All thse Changes

are easy to figure out the appropriate formulas are found

in any catalogue of positions for each star. As to the natur

motions of the wtars, they are small in general and for the

majority are ignored in practice.

Hence, if we know the coordinates of a star we can alway

find it in the sky. But what accuracy is required? If we

only need to find it in order to then determine, let us say, 

the spectral class, or analyze the variability of its luminos

it is most often sufficient to know the coordinates with an

accuracy down to 0.1 min for the right ascension and 1' for

the declination. It is not necessary to allow for any other

subtle effects, only properly account for the precession and

nutation, and even this not always. Indeed, the coordinates

of the star can be taken from any catalogue at all. For

r. example, the Astronomical Annual of the USSR (ed. V. K.

Abalakin) publishes, among others, the precise coordinates of 

ry ^ 

685 stars with a precision down to 0.001 s for the right

ascension and 0.01" for declination, as well as a series of

tables necessary for astronomical observation. However in

the ^ajarity of cases such high precision (especially for 

amateur observations) is not needed, and some-Limes is even a 

hindrance. It is therefore more convenient for amateur astro

mers to use the "Astronomical Calendar", published by the All

:
Union Astronomy and Geodesy Society (VAGO).

The "Astronomical Calendar" consists of two parts -

Permanent and Variable (annual). The permanent part (Astron

miches}:iy kalendar', Permanent Part, 7th ed., Nauka, Moscow,

1981) is a reference work on all the main topics which may

come up in amateur astronomy. It contains the basic concept

of general astronomy, spherical and theoretical astronomies,

astrophysics, describes astronomical instruments and the met

of using them and imparts instruction on all the basic types

of amateur astronomy observations a_d their mathematics. Th

main section contains 37 tables on all the branches of obser

vational astronomy whose data do not depend on time, includi

a catalogue of all stars brighter than magnitude 4.5. This

catalogue gives the name of the star, its magnitude, the

spectral class, the right ascension (with accuracy of 0.1 s)

and declination (with accuracy 1"), their annual changes due 

Al precession, parallax, the natural annual motions, the radiat

4_z

speed, the color index and galactic coordinates (with accura

of 1 0 ). For almost every star information is given as to

variability, multiplicity or physical peculiarities.

The "Astronomical Calendar" was founded in 1895 at

Nizhniy Novgorod (row Gor'kiy) by a group of amateur astrono

Its publications attracted many of the outstanding astronome

of the USSR. Since then, 86 editions of the Variable part a

7 editions of the Permanent part have appeared. The result

is a useful reference work, for consultation by not only ama

teur astronomers, but also professionals. The Variable part

(e.g. Astronomicheskiy kalendar'/Yezhegodnik, Nauka, Moscow,

1903) consists of two sections, the first giving the ephemer

(the majority calculated from data of the "Astronomical Annua

of the USSR"), while the second presents supplements which

j publish articles on current topics of modern astronomy.

72
Contrary to the stars, the planets, Sun and Moon change

their positions in the sky each day and, moreover, with

irregularity. For this reason ephemerides are used - tables

of the positions of the planets, Sun and Moon for a series

of consecutive moments of time. The ephemerides are computed

by the 1TA AN SSSR and published in the "Astronomical Annual

of the USSR". The intervals of consecutive moments of time

are chosen tc, er-:able interpolation of the data given in the

tables to any 4 nterim time, without loss of precision,

The "Astronomical Calendar" first gives the ephemerides

of the Su.an and Moon. For the Sun it indicates in hours and

minutes the rising and setting (for 0 h global time) the

azimuths of the points of rising and setting (in angular

degrees), the equatorial coordinates and declination, the

Julian dates, the time equation, the star time at Greenwich

midnight, and several other data. For the Moon, the times of

ri>ing, culmination and setting, the azimuth of the points of

rising and setting, the equatorial coordinates and the visible

angular radius. Also given are data on the phases of the Moon, 

the conjunctions between the planets and the Moon, and the

positions of the Moon in orbit.

All this information for each calendar date is presented

for 0 h global time, i.e. Greenwich midnight, while the data

on rising and setting are given for a latitude of 56 1 . For

other noments of time and points lying on another latitude

or longitude, the appropriate conversion of the ephemerides 

must be done. To avoid confusing the reader or computational

errors, all the tables are furnished with circumstantial

"explanations of the ephemerides", which distinctly 

to do such conversions, giving the necessary formulas and 

examples.

For the planets their coordinates are published - the
right ascension (with accuracy of 0.1 min) and declination

(with accuracy 1 1 ), moments of rising, upper culmination and

setting (with accuracy 1 min), the azimuth of the points of

rising and setting (with accuracy 1 1 ), the angular diameter 

the visible disk, the phase and stellar magnitude of the

planet. To use the tables more easily, they are prefaced wi

4

a verbal description of the conditions of visibility of the

planets in the particular year.