Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1847-07-24
PROGRESS OF ASTRONOMICAL SCIENCE.
FROM THE NANTUCKET INQUIRER OF July 81
Lieut.. ]. NJ. G1LIrss, U. S. NJ, Washington.

FROM THE NANTUCKET INQUIRER OF JULY 81
THE GREAT TELESCOPE AT CAMBRIDGE, (MAss.l
To the Editor Of the Inquirer Permit me through the
medium of thy paper maze known the result Of
ngs opportunity, which, the 18th instant my rich
privilege enjoy in the examination of various celestial OBJ
ects with the gigantic Equatorial Telescope recently erected
in the new Observatory at Cambridge.
1t is known to the public generally that for several years
past preparations have been progress Cambridge for the
mounting of this noble instrument, which,, during the same
PERIOD has been in of construction Munich in Ger
many In view of the immense pains and involved,
interesting and fearful question whether its perform
would equal the ancpaions long and anxiously in
dugcd by the parties interested and before speaking of this
it may be useful briefly advert Of its properties
though far extended and scientific description of it
will doubtless be prepared by the able director of the Obser
vatory, Vim. c. Bond and ultimately published by the com
mitee Of examination.
The pier which it rests is of masonry, consisting of
blocks of granite 1t is ustrum of cone 20 feet in dia-
meter at its BASE and its top and about 40 feet in
height its base however, twenty feet below the surface Of
the ground On its fiat and level top is placed the PEDESTAL
to which the telescope attached huge block Of gra-
mite, thirteen tons in weight handsomely wrought and of
construction adapted the equatorial apparatus consisting
ponderous of BRASS and weighing with the tube
any not less than four and yet so ngenousy and
perfectly friction evaded that the merest child can give it
motion, and direct it to any point in the heavens
The obectgass Of the instrument is fifteen inches in dia-
meter in the clear its focal length is twenty three feet and
the length OF the instrument including the sliding tube, about
twenty-four feet.
That the reader may not deceive himself by comparing
these dimensions with those of the telescope constructed by
Sir William Hersche the greater recently made
n,,T L.
telescopes with metallic mirrors and for equal.duty with
the exception of what termed spacepenetratng power
must greatly exceed in Suffice to say them that the
telescope at Cambridge is Of the reacting kind optical
duties being performed by lenses and obtain lens of IF
teen inches in diameter Of sufficient purity represent the
object in perfect shape and color under high magnfyng
powers art of nconceivable difficulty, and present.
believe has been successfully accomplished by any other
establishment than the in which this telescope
featured The secret impaired by the amented Fraun
hotter, and fearuy tenacious they of the mnua Of
the movements that it is said they unwilling any
other poker to stir the melted than that which
poyed by that ustrous larger refracng telescope
has been in successful operation in the world
Iii Of corresponding size with the boosted instrument at
the Imperial Observatory at Pulkova manufactured at the
establishment; but the Cambridge lens is warranted
be good, and by the maker believed to be better This
also the opinion of Smms the celebrated manufacturer
of England who employed inspect the lenses side by
side. The immense labor necessary in mounting and adjust
ing instrument of this construction and magnitude with
previous practice experience, greatly diminished
by those preparations which the skill and ingenuity of the
director enabled him effect, while the instrument and its
various equipments in Germany but the period since
its arrival has been sufficient to render the adjustment
perfect, ii present pretended to be fully prepared
for
To counteract the apparent diua motion Of the celestial
Objects which is continually throwing them out Of the field
Of ordinary telescopes "a great annoyance especially when
high powers empoyed,) clock work attached TO the
equatorial axis constructed give to the instrument
quiet and steady sderea motion, contrary to the motion
the earth, and which by slight modification may be applied
to the solar lunar motion but it is generally sufficient
when adusted to star The effect of this arrangement is
keep the object several hours constantly in the centre
the field of view. ..
The night of the 9Th was Ivy means favorable one.
With the exception Of scattering cr, was cIoudess but
the atmosphere was smoky had been for the previous
fortnight The first obec, to which, my request the ee
scope directed the planet Venus invisible the
naked eye being yet daylight The instrument was, how
ever adjusted right ascension and decnaon Of the
planet and the clock work set in notion when the object
made its appearance the centre of tho field and although
yelled with smoke and obscued by daylight met the eye
with glare What will be the effect OF a view Of this pa
net in the absence of twilight in clear autumnal evening"
can only be imagined The planet only fourteen de-
grees from the horizon The intervening dense atmosphere