Daily Yellowstone journal., 1890-02-08
THE CAMERA AND THE HEAVENS.
The Methods Employed aud Uses ct Pho
iusraphing the stars.

A mariner, who drawing near
port nj night, is guided by the two en-
trance lights Ia the harbor. Ashc APP.
proaches he sees these two lights sepa-
rate, while when he leaves the harbor
at night the further he gets away the
closer do the lights appear 10 draw to-
gether. In a similar ann the AS
tronomcr observes the lights of the uni
verse to learn whittier the great So
lar system is tending. His bcacons are
the stars, and in that region toward
which the sun is approaching the stars
seem to spread away from each other,
while in that opposite region from
which the sun is retreating the stars
seem To draw in more closely together.
Indeed, it is only by observing these
changes in the apparent places of the
stars that we learn the fact of the suns
motion. To investigate the subject
properly we must employ a large num-
Der of stars, and w must wait a very
long time i'm order to measure their
displacements with precision. This is
exactly the kind of work in which the
photographs may be expected to help
us. Every plate will be carefully
treasured up, TO be compared with the
plates taken in subsequent years, and
from the changes in the apparent
places of the stars we shall learn with
more accuracy than We have hitherto
been able 10 acquire the true facts with
regard Ia that mighty voyage through
space OF which our sun and all his
system is iourneying.
But there are many other aids which
photography renders 10 us in our eff
forts To learn more of the skies. One
of the most difficult problems is that
of determining the distance Of stars.
This depends upon very careful meas
urements made between a star and
other stars i'll its neighborhood. 1t
often takes an hour To measure the APP
parent distance between two stars in
the ordinary way, but in that hour the
telescope might much more proiitably
be employed i'll taking a photograph
on which 100 stars, or perhaps more,
would be found. and the distance be-
tween every pair Of which would ad-
NIT of being determined with accu-
racy.
Still, other and more marvellous APP
plications of photography 10 the heav-
ems have been made. The greatest
telescopes are often directed 10 the OBJ
~seryatiOn of the nebul1. or stains and
patches of light situated at incredible
depths in space. There are thousands
of these objects known TO those as.
tronomcrs who assiduously cultivate
this branch of their science, and the
nebutI are all so faint that, with a
single exception, they are invisible TO
the unaidcd eye. The exception is the
Great Ne6ulH, la Andromeda, which
appears like adult spot of light, Just
visible rs glimmer on the darkest
night. For ages this object has at
tracted the attention of astronomers,
and numerous drawings have been
made of il. But the nature of the
Great NebulH was never understood
until Mr.. Isaac Roberts obtaineda mar
vous Photographic picture of the nebu-
lac, after AN exposure of four hours. 1t
was then seen 10 be composed of a
number of rings Of gaseous material,
apparently in a highly heated state,
and doubtless going through some
great process of transformation.
Hardly less wonderful is the photo
graphic picture of the Pleiades. This
well known group of little stars ex-
hibits no nebulosity in the telescope,
but after a long exposure a nebula is
depicted on the plate. Here photogra-
ply has been the means of telling us Of
the existence of a mighty nebule sur
rounding the Pleiades, but which was
quite unknown till the photograph
showed il. Even now il has never
been actually seen in the telescope
Sir Robert Ball in Liverpool Courier.