, 1870-08-28
STAR-CATALOGUING.

What i. Et-iug Done in tt,c Chicago
observatory. mud EF>csvhcrc.
The following Interesting report WAS pre-
sented to The American Scientific Association, |
1t it's meeting in TROY, n T., by Truman Il. |
SaiEcrd, Esq, the Asst. ononer as the Dearborn
Observatos. in thir city:
"Thc great ASTRONOMER, Dessel, cherished |
the deeign Of making complete and accurate
tnue inclusive; bat the actual completion Of |
tht sigu has fallen to the third generation |
OF his astronomical tt scen'!ants, The pupils IT
his Pupils, under tlle lead Of that most emil |
neNs u aN tho n.cn wao lccCtroI ulEect ILL., |
ktrHctlon flo1A ltill-Argelapltf, |
''Ibe execution ri tho w.pEk has been d. |
vidcd among the ob.crvhtnries from Palermo I
tu CLristlania in latitude, aud fzou, Kaz1u to
Chicago ip longitude: 70 far, and farsLe., in
deed, have l,rtsels ideas penetrated. Before
this work could be dunc, great preliminary
laboio mus: be uudct1.keu, aud lEese have
betn OF enurllulls yaine tu aetTC uOll.rH. Who
among them does not appreciate tho value Ut
Hceetl's a,ld ArEclande1s Zones sud tue great
work l. oi,e Of greater extent, aud re.lu res
gres' ct expenditure OF time.
:. Eeseel and lis assistants employed About
twelve ytszs uIuu the zpnrs between o. aud
i5e 1t dfclination AEgtiander with lis as-
ristsn:s we're five xna1e extending the zones
fr.1n :,le to sos. ArEelander, Sshoenfeli,
aud kruger lab1.ed al..ut tight years upon
the Do.. .ncr 0ureLH4uekeruu6. making tAus
abuIt sixty se3rs' ol.-ersatlens.-wlne the
prlseh: noIk will require for its ful1 cou,p!c-
tlOn alout Aftecn 0E.eryatuEica for about ten
years apiece: c., in the northern helnist.lcre
nl,ne. to Which the largest sl41c Ut the PFC
liu.iLaty obee1sat.uus were devoted. t~tlve
obFcEsatories for biz years apirce,--or not
less than Que hundred yea1s'
eiuEie astronomer wo,k 20 long.
= Tic ubjtct oI the pce- cut paper is to it,
dicAte the ends 10 be attained, tho mole Ct
working. aid o',.er detail. about this work. It
il tltetsd ,u oL.-la accurate Positions for the
vo,ks ., this kind h.ve been
moro or lcssiLcomp1etc. The Ascuiacs desired,
| greater no= tiau was formerly attaiue.i. Is
e3l7et sea by tie fzosaa error Of about one-
half tecoud Ut epacr iu either co-ardi.ate.
| vatioce.
s'The numher Of stars to ,e included i'll the
catalogue ia about 100000: Tut une-haif Of
them-i1l tho southern tui-phere-mu.,
Wait fs'E the preliminary work p;,N uotig.
1.-The practical ends Of :.s series OF otse1va.
tious will be the fret attained There arc
many stars nf tue rlxth and se:cn.h magni-
tudes get undetermined, Which, when obserE led
| will 9 Of ute to eeoGetic astronomers for lat
:tude aud longitude, aud will often save nucl
| &imf IL theeo p1ublens.
1.-THE theory OF the moon will la i1e1pal b.
larger catalogue Of equitable stars, those q
sma4 planets anu coEuets BY Al accurate da-
termination Of their comparative stars. Tie
examination OF the heavens for uebuln-a
wosk begun some years Ago at Chicago to eu11
rlement the admirable Iabors Of Herechct, n Ar
rest, and others--e1nnot bo thoroughly pros
ccutttl to the accurate determination Of tn,
netuEar positions. Ut we'll even to the cestait
recognition of tLeir identity. without this
catalogue.
- There are nea1is iifts thousand o1,serva
tto'.s OF fainter rtass than the ninth unEni
| t,ale, made 1T Cambridge under loud y dlrec
!io'I, wtcee great Accuracy cannot cScsl b.
properly appreciated without reducing .l.eu
by the help Of the present work, and I lav;
accumulated rome lonr thousand similar Oh
-eIv1iions at Chicago In 4 word. it is ns:es
rary for nearly all the observations which cs
te made with the great equatorials Of III
present day. that = tirt,, accurate. and sn,
baeie shall he laid 1ish the meriJiaa instrr
tnehta, and such ! basis the catalogue no
; | making will afford. Without such basis q
We had painful experience At Cambridge
= much time waE lost, in great many WAYS. il
: working the g1eat equatorial and the obsel
! vas1ons made there are Jet largely unzednce
"1he present serias will possess 20 great
;, | degree Of unity and uniformity that it vi
, eesve to bitd together more closely, and t
, | tt.luce to a common basis, many sc1ttere
l
tome Of the principal ot=eTvatoriee OF th
b world.
: "At present. 60 soon 40 the catalogue
: completed. il will Afford At onco basis q
, ee,ui .z'son with past work: Till within abou
. 25 or ~ years. EE1dleF's observations {
: l.u. i1ttir over 5000 e;azs, aud few hy l.
: c-ille. were almost the only former observ:
= tons which could be compared with much N
! vsntase in the etudY Ut the motions Of Il
universe.
..r1,A p.:.;s1, spe,.;.+:,r @,.s, ,,...,. ~ O -
I ! etsrs contatna very many proper Motion
/ | even large ones. which 1ra quite faii.-iou
r | Owing 10 the numerous eETosH CT I1Axzl ar
: Taylt1, where an Incorrect cid position Of
t st*r Is compared with coEIe;t new ona, II
1t may appear large, when. In reality. snaa
= or, in few cares, email. when reilly OF col
ede1able arnount. But We now have many e
"a celleut series which have gEowa Old euough
:. se:ye II ancient determinations D'igel
"a "a ll7e5) well reduced by cur eoun:rsmaa D
- Gcull: Ialanle'e immense series
- over 5O.OfU observation made beswet
~ 17:1 and 1902: i'iazxi's aud G7opmtrilSe
catalogues. tcgetlier Including l0.0hl stars T
i. Tea:edly observed; nj these s:azr. though t
:. etst1ved in De.eerH aud A1eelandera Zone
"a l., Taylor'B and 1taic.ldes ;C4taloEue.. q
- elseN here, caanot but be much better inves
= gated AZ 10 proper mutton wlen the me
r. epoch os reletetmsnation is nearly twice a. I
70 treu that OF the original catalogue.
i or course, many more stars will now ini
/. cate sensible pruper motion, and il 30. will
10 At once observed with great care, in a4ldisie
n the regular dete1minA ion Of previously 1ou
[e ful cases Of proper noson will BE- at on
,E cleared up. At Fiaxzi and Taylor will nas &c
/. troll eacn other inete.d Of increasing the efft
r Of each others errors; the 70 tr.'lbie-o-
n CONSTANT erross III Eessel's Z3nes sill t;eco1
as manifest and can te It once c0rre:'eI: And
~ al THESE matters the conlpleteEe-s nt I
to Preseat work--tlua largely 10 tue Eoa"
at Dnrchnu=rerung-will 1'ressu: sezs ST.
n losses Of tlue III tie fntnFe-
n. .' Bssrars tie oldez ob-=1re.s aase nv
is tioued. Totils Mayors ot=sTrA.!o+is 'tn
ia | ncw Of E1ore extensive use. n he j. eFe'
~ 4t,ere cou,,oi:.t By PIAZZA aad Taylor;
h. tie brilliant ealsSy OF oc=e1vc:s rS5nn!
A. with Res.el. nf,d s;tuye. come G! "1oal
Is. Dsw iviEs. will hstseif oo:eisa4ons ~ s t,,as
~ eire uf 70, er motions. Thus thu etars
.s' Esi,. four or nve tines By Bcs.el mi stE1
1+tw+eu ls:U End 1880, aud bk an earlier r.
- esa.s autlority. Az 20 much he,tes descsmis
OF for tie ast than Bsailey's ssass no. fe17se
@ @,eS III lie prediction Of the right ascension
~, the Pole etas itself has been siucs Gsase
n pitl4ln few years, matter o1 1aitt sensl
iii uncertainty, owing partly to Bra1ieEs ?
in eon.l et.rstien, which. to BE- really 5ssoSnn 1
M [Es strive sad Deseel t. old observations.
M In ny paper on the right a=c
~ ~ .:cu of ths Pcle star, I pointed I
80 this fact, yhiel haa been since recognized
bar American ard foreign Astronomers. and &C
~. uuo1 in ,l.eir works. The time il ra?idly
Id iuol;ou ID space. md related problems, )
r,ii ~ Mr.. D1ton's Stag-dtifs.'
On .tNhsn We hare tie material derived Il
,era ! tie LOG, COO staTt already observed with q.
re, accuracy, ecGpAtc1 with the prasant vol
K. will be Probably eriaeus that. sa:, IL. 900