CoudeWhen using the coude focus, there a few hardware items that observers should be aware of.
- There is a polar axis cover in the coude slit room. It is the observer's responsibility to remove the cover before observations begin and when they are completed at the end of the night.
- When observing at declinations greater than 55 degrees, the 5 mirror system must be used. It takes at least 6 minutes (maximum 8 minutes in normal operations) to switch from the 3 mirror to the 5 mirror configuration.
- When observing in 5 mirror mode, the throughput is 60% of the throughput in 3 mirror mode (measured by E. Gates 2013 Dec 29).
- The southern limit for 5 mirror mode observing is 20 degrees Declination, so that objects with Declinations between 20 and 55 degrees may be observed in either 3 mirror or 5 mirror mode. However, 3 mirror mode is generally preferred due to the decreased throughput in 5 mirror mode. There may be some additional light loss in 5 mirror configuration for Declinations less than +22 degrees.
Last modified: Tue Dec 31 17:46:23 PST 2013