Abstract
The 84-inch (215-cm) stellar telescopeTwo focal positions are available: a Ritchey-Chretien f/7.6 with a scale of 12'.'7/mm, and a coude position of approximately //30 with a scale of 32/mm. By rotating the entire secondary mirror assembly, and by swinging into the beam the first flat mirror in the 5-mirror coude system, the telescope operator can change from one focal position to the other in about 15 minutes. The observer can thus easily use both focal positions during the same night at the telescope. A Cassegrain spectograph employing either photographic or electron image tube equipment, a photoelectric photometer, and a direct photography camera are available for use at the Ritchey-Chretien focal position. An offset guider is available for on-axis instrumentation. The coude spectrograph has a collimator beam diameter of 22 cm, two 204x254 mm gratings of 600 and 1200 grooves/mm, and 4 cameras that give dispersions of 2.2, 8.9, 13.5 and 24.3 Â/mm with the 600 grooves/mm grating used in the 2nd order blue. The spectrograph is equipped with an exposure meter.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
