The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1901-01-02

eye end of the telescope. The order
of the stars, the secrets of the sky, I'M
veil themselves before the patient stare
of the Photographic plate. AS Her
/ schel has said. 1.-The camera is the re-
tina that forgets not It discerns stars
beyond the range of the best teles-
copes. In the atmosphere of Paris the
satellite of Neptune was never seen by
the telescope; every part Of its orbit
was measured on a Photographic plate
The lens of the camera is of more
astronomical value than the lens Of
the finest telescope. More accuracy
obtains in measuring a plate than was
possible in visual measurement. One
five hundred thousandths Of an inch
and less on a Photographic plate fur
nishes data for accurate star measure
! ment; where the telescope will show
but 100000 stars. the sensitized plate
exhibits more than 10000, 900.
Again, owing to the great sensitive
ness of modern plates the images
thrown upon them may be highly mag
nified while the exposure is kept very
short.
Five e-thousandths of a second is
all the time required to photograph a
star of the first magnitude. Stars Wis
IDLE to the naked eye may be photo
graphed in half a second, those of the
fourteenth magnitude requiring thir-
teen minutes. BY exposing a plate for
an hour all the stars down to the four
teenth magnitude inclusive viii be
marked on the plate, each in proper
ton to its power and the duration of
the exposure.
Though light travels at the incon-
ceivable velocity of $4,000 miles a Sec
ond, yet light from some stars in the
range. Of the telescope takes 5.760 years
to reach the earth. We may see on the
Photographic plate pictures of stars.
not as they are, but as they were per-
haps half a million years ago; light is
still reaching US from stars which
have long since become extinct.
It is possible that the plate of the
camera is to-day catching from stars
light which has beer travelling earth
ward millions Of years-which may, in
deed, have set out toward the earth
before this planet came into existence.
The first star photograph was a da-
guerreotype of Vega taken at Har-
ward College July II, 1850. The young
er Bond. by the collodion process, OBJ
tanned in 1857 photographs of stars of
the first magnitude.
No serious effort was made in stellar
photography until after 1882, when Dr.
Gill photographed the comet Of that
year at the Cape of Good Hope Obser-
vatory- He attached an ordinary por-
trait lens with a two-inch aperture and
a focus Of eleven inches to the teles-
cope, using the instrument as a find
err to the camera. Photographs last
ing from half an hour to two hours and
twenty minutes were taken.
The new Photographic map IS pre-
ceded by a visual map commenced a
quarter of a century ago by Bonn and
completed by Highlander. Its object
was great star census. It was be-
gun in the Northern Hemisphere and
brought by Schonfeld to within 70 de-
grees of the equator. This ''Durch-
musterung,' or roll call of the stel-
lar army" is divided into two sections,
and tabulates 1885, 900 stars.
Stars not entered in It have no off,
cial existence. Should they vanish the
fact cannot be attested should they
brighten into conspicuousness they
must be regarded as new for lack of
previous acquaintance. Whatever is
known of the distribution of stars is
taken from that enumeration.
The Photographic map proposed by
DR.. Gill win extend from Schonfeld's
zone to the South Pole, and will in
clude all stars up to the fifteenth mag
nitude- The fourteen magnitude stars
are on the limit of faintness Be
yond these stars Photographic images
are vague.