Recovering from a Stall

Jun 14, 2021, P Gabor et al. ✔✘
Control room :!: Mirror cover must be open. :!:
Control room 8-) If you want to close the dome slit (may be a good idea esp. when windy), close the mirror cover (assuming that the breaks came on when the stall occurred), than close the dome slit, and then open the mirror cover again.
Control room Turn on the dome floodlights
Control room Breaks off :!: Be ready to set the breaks again if the telescope slumps in elevation when the breaks are released (watch the telescope in cameras, 8-O and watch the elevation value in TCSglue)
Control room Keep dome tracking on
Dome, lower lvl Inspect the “flippers” and find the double-headed bumper. You will need to spin the telescope back to its stow azimuth. Remember that:
=) the double-headed bumper “lives” in the South
=) from your vantage point at the dome's lower level, a flipper may show a green patch or no patch; you can never see a red patch from there
Safe (recommended) Less safe
=) if both are green, simply align the arrows meticulously if both are green, simply align the arrows within a few inches
=) if one is green and the other has no patch, spin towards the latter, flipping it to green; then keep spinning until the arrows align perfectly if one is green and the other has no patch, spin towards the latter, flipping it to green; then keep spinning until the arrows align within a few inches
Basement Disable the hydtrostatic bearing: Turn Stage 2 off. Does not apply
Dome, upper lvl Move the telescope to zenith Step onto the telescope yoke platform carefully (avoid imparting angular momentum in azimuth), and move the telescope to zenith
Dome, upper lvl Turn the derotator (considerable force is required) back to home, untwisting the cable bundle Still standing on the yoke platform, turn the derotator (considerable force is required) back to home, untwisting the cable bundle
Dome, lower lvl Align the Azimuth arrows accurately
Dome, upper lvl Bring the dome to its home position (gently spinning the encoder wheel)
Basement Enable the hydrostatic bearing: Turn Stage 2 on. Does not apply
Control room Set the breaks
Control room Close the mirror cover
Control room Close the dome slit (if open)
Control room Turn Thermal control off
Control room Stop Autocollimation
TCS room Reboot VATTtel
Control room Close and open TCSglue
Control room Start Autocollimation
Control room Turn Thermal control on
Done!