Interior HAS of David Dunlap Observatory dome showing top of telescope cage and open shutters, of cage being lowered, of Dr Donald Macrea in cage. MSs of Dr Macrea at top end of cage, putting cover on Cassegrain mirror, of the astronomer at bottom end of cage, covering primary mirror. CUs of iron arc light being lit, of top end of telescope cage as light is gradually shutting out by closing shutters. CS of telescope drive in operation, TILT UP to cage and to open shutters. CU of top end of cage, of shutters being opened. ECU of crosshair of telescope star finder centering on star. CU of Dr Macrea, TILT UP to MS of dome shutters opening. MS of whole telescope, Dr Macrea at work adjusting telescope. Interior shot of cage showing cassegrain mirror. CUs of star spectrogram, of triangular star finder with crosshairs being positioned on star.