Saturn, photographed by Dr. Lowell, March 12, 1915, showing the ring open to its widest extent 
THE PHOTOGRAPH IN ASTRONOMY 
By E. C. Slipher? 
Lowell Observatory, 
URING the last two decades the 
application of photography to 
researches in astronomy and 
in other sciences as well, has been fraught 
with advances. 
Through its use in astronomy we have 
facts 
numerous important 
learned many new which have 
confirmed or refuted the old theories 
and created new scientific belief; and 
furthermore photography furnishes per- 
manent pictorial record of the evidence, 
accurate and incontestable, that all may 
see and believe. No argument carries 
a conviction equal to that gained by 
seeing the thing oneself. 
Excellent photographs of the great 
planet Jupiter have been made through 
the 24-inch refracting telescope of the 
Lowell Observatory, Flagstaff, Arizona. 
They show at a glance the conspicuous 
belted appearance of the visible surface— 
probably the zoned formation of the vari- 
ous gases of a very dense atmosphere 
beneath which we seldom if ever see — 
and innumerable, finer, wisplike mark- 
1 Mr. E. C. Slipher has been directly associated 
with Dr. Lowell in his work on Mars at the Flag- 
staff Observatory for many years. He has gone 
also on various expeditions, among them one to 
Alianza, Chile, in 1907, to observe Mars. 
Flagstaff, Arizona 
ings interlacing the belts. Photographs 
of the planet showing different longitudes 
present a varied aspect of these belts, 
and the photographs taken in different 
years indicate many evident chaotic 
changes there. 
Across the ball of the planet Saturn 
there will be noted in the photographs 
quite similar although less pronounced 
beltlike markings paralleling the equator; 
this indicates a like condition of the 
atmospheres of Jupiter and Saturn. 
The unique rings about Saturn are re- 
markably well shown in_ photographs, 
with Cassini’s division distinetly visible 
all the way around, separating the two 
brighter rings. The third and inner ring 
—the filmy crépe ring —is too faint 
to show except where it crosses the 
ball, without an overexposure, although 
much of the original definition is lost 
in the enlarged reproductions due to 
the separation of the silver grains of the 
emulsion. It will be seen that the ball 
of Saturn shines through the outer ring 
where it crosses the planet on the lower 
side; this tells how ‘very thin the rings 
are and evinces their meteoric constitu- 
tion. The definition of these planetary 
211 
