Evening capital news. (Boise, Idaho) 1901-1927, 1912-12-25
L0aaAml@es~...
COUNTING THE STARS.

Nearly two years ago Greenwich observatory began a
81 The stars. iew weeks ago the British Astron
emef ROYAL announced that the count was almost
plete The work probably will be finished by January
when tile results 81 studying than fifty million
will BE- published. s. Chapman Of tic Royal observatory
in an interview in the London Standard, said:
"Of course not counting each individual star
that Would take hundred Years. We counting var
ious OF the sky which, in the aggregate amount to
one-teth of the total and then the amount will be
multiplied bE ten lhe counted areas have been selected
system which should yield fair average that the
final figure probably total of something fifty mil
Ions-vil be approximately correct"
Mr. Chapman explained that the counting is carried
out bJ means OF photography. The whole sky has been
Photographed 206 plates, each IS inches square being
necessary. Each plate records from 10000 to 100000
starry images the result of two hours exposure in the
southern hemisphere, or hours 20 minutes in the north
en hemisphere. by using specially designed ten-inch
chromate Ions stars great aintness down to the six
teenth and seventeenth magnudes have left impress
sonon the plate The star images then counted under
h9h-FoWcr microscope. ioie again short cut TO an
average s taken 10 count every image a single plate
would taNe I've assistants fortnight only sample
areaSon the plate examined and the average for the
hhee plate 8 arrived at by simple proportion sum. The
plates ruled into sections ~ reseau lines one degree
the plate and other squares and reetangles Of definite
area marked EFT ~ measuring il progressive stages Of
three degrees starting FROM tie any part Ct tie
plate The stars in each counted then the
hers and tie areas faalcd, giving the basis for the
finding q the average tatal on the whole plate
The densit4of tho star clusters varies enormously
dfed stars II area 81 forty square minutes while iii
other places takes Of eight hundred square min
utes 10 get sixty stars But average should be
ably accurate, Vhrn have finished we shall have
counted the stars il live thousand separate regions the
sky
Before the work is completed the total number Of pho
togfanhs taken will thus be els The standardizing pho
tographs for the northern hemisphere being taken at
Greenwich huf tile work has been DELAYED through lack
Of clear weather The original plates Of The southern hem
lshere now being counted, mostly taken at the
Cape o Good Hope and Johannesburg
The counting and comparing is done under Mr. Chap
man careful supervision and correction by two bows of
about H. who work according to definite code of simple
rules Their entries being made ia specially designed books
The photographs were originally the property Of the we'll
known astronomer Franklin Adams, f. r. A. S. who died
recently Al the original photographs Of the northern
hemisphere were taken by him and his assistants al
his observatory MerHel Hill in Surrey and those of the
southern hemisphere taken abroad in accordance
with arrangements made BY him. He first proposed to
count the stars himself but decided that the task was too
much for him and handed his unique collection of mega
tves to the Astronomer ROYAL.