New-York tribune., 1901-01-13
MEASURING STAR PLATES.
UNIQUE ASTRONOMICAL WORK DONE AT
COLUMBIA.
THE UNIVERSITY BETTER EQUIPPED WITH
BRAINS THAN APPARATUS


BRAINS THAN APPARATUS.
The announcement that star plates sent clear
the continent from the Lick Observatory
Columbia. for measurement naturally raises
the question how 1t happens that the latter institu-
tion is the only in America where such work
can be performed. and also provokes inquiries as
10 the nature of the labor itself. The facts them
selves certainly in the highest degree credit
able to that department of Columbia CniVersitY
Of which Professor J. K. Rees has long been at the
head
The late l., VI. Rutherfurd of this city made
large number of photographs OF the sun, moon
and with instrument of his own con-
struction. Professor Simon Newcomb said OF these
pictures only q few years ago that tn excel
lenoe they had never been surpassed These
photographs all presented to Columbia Uni
versity upon AIR. Rutherfurd's death in 1852. And
since then the work of measuring the celestial
latitude and longitude of the images on the star
plates Degu, by him been continued under
the direction of Professor Rees. The publication
of the results has been made possible by the gen
erosity of Mr.. Rutherftrd Stuyvesant.
With money obtained from other outside sources
Professor Rece has been able to organize regular
staff for the performance of this work The i'm
mediate measurement of the plates is conducted by
four young women all college gradua tes-Miss
Harpen of Smith; Miss McGill of Swarthmore.
and Misses Tarbox and Davis of Yassar. The
data thus obtained then subjected TO difficult
mdthf ttlCa' treatment py the cOnlpuJefs Di
Harold Jacchy and DR.. s. A. Mitchell have been
associated with Professor Rees In this portion OF
the work In passing II may be remarked that
the Naval Observatory has invited DR.. Mitchell 10
accompany tAe Government expedition to the
East Indies May, observe the total eclipse
of the sun, and II Professor Rees raise $500
or 5000 pay for a substitute this requisite leave
of absence viii be granted.
The first step In the measurement of star photo
sraphs is conducted by means OF special machine.
The plates are negative. and the stars are little
black dots on them Through the centre of a
plate draw two lines at right angles: and the
ieast distance OF each dot from both Hne, Is ascer
tanned and recorded. Rutherfurd generally had a
well known star at the centre OF each OF his plates
but other astronomers have not followed that plan
and II becomes necessary 20 put a temporary mark
there TO begin with The tiny asteroId Eros, in
which the astronomers row intensely interested.
q change In position among the stars be de-
tected in 4 few hours The solution OF che great
problems for which these observations OF Eros
have Just been made requires the most careful
measurements OF the asteroids position well as
that of the stars each plate. Before Professor
Rees and his staff are through with the work they
are likely to receive TWO hundred plates from the
arst fev davs OF October have vet come 10 hand
Two three years may eiapse before the computa-
tiors reductions are completed.
fact that often cOmIlicates an undertaking of
this kind is that the stars though supposed to be
stationary. sometimes have motion OF their own.
Hence they cannot be used standards for COM
parison until their own position Is accurately de
termined For instance. one of the rcest bits OF
work ever done Columbia was a set o. observa-
its axis FOR this hlytStlSaIiou nI,y-eiRhI stars
employed. An elaborate examination of no
mense amount OF calculation determine posi-
lively the correct latitude and longitude OF these
normal position could be detected. This important
preliminary consumed the best part OF three years.