196 
40 
ALL DIMENSIONS 
IN CENTIMETERS, 
30 
“3 
= 
2 0.26 THICK 
Zz 
Li 
q 
20-05 
(ep) 
10 
0 
ANNUAL REPORT SMITHSONIAN INSTITUTION, 1948 
ALUMINUM 
| 0,23 THICK 
Ficure 3.—Schematic diagram of counter telescope arrangement in warhead for the 
March 7, 1947, missile. 
Astrophysics and Composition 
Because the earth’s atmosphere had 
limited spectroscopic observations of 
the sun to a lower wave-length limit 
of 2863 A. (22), astronomers have long 
been looking forward to the time when 
the unknown far-ultraviolet region 
could be observed. Even though 
balloons could reach altitudes of 30 
km. they were not quite able to pierce 
the ozone layer and, because of the 
ozone absorption band which lies just 
below 2900 A., the lower wave-length 
limit observed at 30 km. was about the 
same as it was at sea level (23). 
A rocket which reached altitudes of 
170 km. and higher should prove very 
valuable in further solar spectral 
studies. To get such a spectrum and 
at the same time to get more construc- 
tive information on composition of the 
atmosphere, a special vacuum grating 
spectrograph, shown in figure 4, was 
designed to fit into the V—2 (6). Two 
small lithium fluoride beads are used 
for obtaining a wide angle of view so 
