UNIVERSITY OF CALIFORNIA OBSERVATORIES / LICK OBSERVATORY

CROSSLEY POINTING & WEATHER LIMITS HOME
Crossley observers should be aware of the following conditions which limit or prevent operation of the telescope.

Pointing Limits
Zenith distance less than 75-degrees to avoid tipping mirror.
Wind Limits
No explicit limits, but when leaves and twigs start blowing in perhaps you're pressing too hard. Usually, before this happens, the tube will shake too much for reliable observations anyway.
Humidity
Close the dome at 95% or earlier if necessary to exclude any and all moisture from the dome. In particular be alert for sudden and unexpected fog formation and do not leave the vicinity of the open dome without being very alert for any sudden change in the weather. If you can see moisture in your flashlight beam, or if surfaces get wet: close!
Ash
Consult 3-meter operator (9-5952).