THE 
JOURNAL OF SCIENCE. 
MAY, 1884. 
I. STELLAR PHOTOGRAPHY. 
By T. E. Espin, B.A., F.R.A.S., Special Observer to the 
Liverpool Astronomical Society. 
t HE great and rapid improvement in the sensitiveness 
of dry plates for photography has at length allowed 
of successful photographs being taken of some celes- 
tial objects. At the Oxford Observatory for some time the 
moon was photographed with a I3*inch lefledtoi on eveiy 
available night, and the photographs have been so perfectly 
taken that they allow of measurement under high micro- 
scopical power. The possibility of photographing the moon 
has, however, long been known. But with the other hea- 
venly bodies the matter is a somewhat difficult one. The 
image formed at the focus of the telescope is so extremely 
small, and the difficulty of following the celestial objedt— - 
whatever it may be — so great, that the results hitherto obtained 
are not more curious than of scientific value. M. Common, 
with a refledtor of 37 inches aperture, has however succeeded 
in photographing the planets Saturn and Jupiter. . With a 
powerful magnifying-glass it is possible to see the ring of the 
former, and the photographs that have been obtained of V 1 ® 
latter show some detail on enlargement. The red spot which 
has been the chief object of interest so long was visible on 
one photograph. The difficulty of photographing any detail 
on this planet will be the possibility of extremely short ex- 
posure ; for the rapid rotation of the planet on its axis, viz., 
VOL. VI. (THIRD SERIES). s 
