SECT. 3] APPLICATIONS OF THE GYROPENDULUM 335 



the altitude of the polar axis were effected by adjustments of the latitude slow- 

 motion screw. The accompanying photographs of the star clouds in the Crux- 

 Argo (Fig. 9). the Sagittarius-Scorpius regions (Fig. 10) and mosaic of the 

 Milky Way (Fig. 11) were obtained by these methods. The moon, sun and 

 brighter planets have also been photographed on a scale of 1 cm/deg. 



The applications of the meridian gyro to other problems in astronomical and 

 meterological photography and theodolite measurements from shipboard are 

 numerous and may include direct photography of solar eclipses as well as their 

 associated flash and coronal spectra, records of meteor and satellite trajectories, 



Fig. 9. Milky Way in the Crux-Argo region photographed on 19 March, 1961, from R.V 

 Chain while under way at 13 knots in lat. 00° 10' South and long. 18° 44' West. During 

 the 30 min exposure (0130 to 0200 G.M.T.) with a Zeiss Biotar of 50 mm focal length, 

 working at//2 on Tri-X film, compensations for roll, pitch and yaw were provided by 

 the Sperry Mark 19 meridian gyrocompass. Corrections for the ship's motion in 

 latitude and longitude as well as for the earth's rotation were provided by hand 

 guiding on Spica. North is at the top. The Southern Cross and "coal sack" appear to 

 the left of center. 



and whole-sky time-lapse auroral or cloud photographs, to name a few; all 

 with the option of placing the observing station wherever geographic and 

 climatic conditions are most favorable. It is worth noting that in the vicinity 

 of the magnetic equator the absence of aurora and air glow is marked, and, 

 being far from the smoke and scattered light of populated regions on land, the 

 night sky at sea is so black that faint celestial objects are often unexpectedly 

 easy to observe. 



