Observers Contract
The primary observer on the telescope is responsible for ensuring that other
users of the telescope during their observing run comply with the rules outlined in the Observers Contract.
Weather Rules
Weather conditions should be monitored with the “wx” command or with any of the
dedicated weather monitors. All domes must close if weather rules dictate that any dome be
closed.
Precipitation: All domes must be closed immediately whenever there is any form of
precipitation or if precipitation is imminent.
Humidity: Above 90% humidity, the observer should monitor conditions. Telescope domes
should be closed if condensation is detected on any interior surfaces or if condensation is
dripping in from the slit opening. If the average humidity is 95% or higher, all domes are to
be closed.
Wind:
| 5 minute average speeds | Single Gusts | Action |
| >50 mph | >55mph or 3 gusts of 50mph in a 5 minute interval* |
Close immediately (no exceptions!) |
| 45-50 mph | >50mph | Work downwind; be prepared to close |
| 40-45 mph | >45mph | Turn downwind at observer’s earliest convenience. |
| 35-40mph | >40mph | Close shutter/windscreens to minimum opening possible for the observations |
Dust: Domes and mirror covers should be closed if high dust conditions are reported. If the
dust monitor reports counts >100,000, domes must be closed. Between 50,000 and 100,000,
observers should monitor the conditions with the “dust flashlight”.
Departing Early
Notify Observing Support, mcd-os@utlists.utexas.edu, if you leave prior to your scheduled departure.
Accident with the telescope
If there is a collision between the telescope or instrument and any part of the dome or
anything within the dome, the telescope must be left where it is at the point of contact, with
drive turned off, and a member of the staff must be called immediately.
Note that both the 2.7-m (107-inch) and the 2.1-m (82-inch) have collision avoidance charts on the back of the laminated page with web addresses. Ask for help understanding these if they are not clear.
Dome Closure Rules
Upon closing: Any observer who closes because of weather conditions should notify the other
domes about the conditions. If one dome is required to close, all domes should close.
Reopening: After closing a dome due to weather, the observer must wait a minimum of 30-minutes with conditions at a safe level before reopening.