Beginning of the Night

30 min before sunset:

1. Check temp4m and weat
2. Orient the shutter eastward to make sure no direct sunlight will enter the dome.
3. Open the dome (before opening mirror cover!)
4. Open the mirror cover
5. Turn OFF mirror cooler.
6. Turn ON sucker & extractors
7. Turn OFF dome floor stirring fan
8. Make sure all passageway doors are closed, especially the glass door in front of the lift at GR floor, the cryocooler compressor and pump rooms.
9. Turn on CORR (See why [1])

Just after sunset:

• Open the lateral sliding doors.
  Note: if wind is greater than 15 mph on average wind buffet on the telescope may produce elongated images in which case the sliding doors should be closed. Under any circumstances, the lateral doors must be closed if the wind speed is greater than 25 mph.
• If working at f/8:
  • Turn ON the chimney fans
  • Turn F/8 OFF [Ed: WHY?]
  • Check collimation [2]
• If working at Prime:
  • Nothing special for Prime