Problem(s) Encountered:

The problem from last night repeated itself twice, where the telescope jumped around and the mirror airbag forces fluctuated between 15-70. The first incident occurred close to the same time as it did last night - around 0730 UT. It subsided quickly and we continued observing. The second time was around 1030 UT, and lasted for at least 30 seconds. We slewed back to zenith, turned off tracking and drives, and waited half an hour. After that it was fine.

Solutions:

Problem is with HP1, specifically where the connector plugs into the electronics on the back of the telescope.  Pulled the cable for the H1 hard point sensor and cut the connector off.  Redid all solder points to the wires as cleanly as I could (have I mentioned how small these wires are?) and tested the cable for continuity.  Reconnected the cable and brought the airbag system back online and all appears to be functioning.  Slewed the telescope around while watching the sensors and saw no failures.  The real test will be a few nights on-sky as the problem was intermittent at worst.  If this turns out to not solve the problem, the issue likely lays within the female end of the connector, on the electronics box itself.

If this occurs again, the simple workaround is to swap the system to “pressure-equalization” mode, by disabling feedback associated with HP1.  This is simply done by typing h1 at the airbag keyboard.  Do not expect an echo of the command.  Once issued, the observer will notice a string, indicating that HP1 is disabled and that the airbag pressures for all three subsets attempt to equalize pressure between them.  It is also worth noting that while disabled, HP1 measurements will still read out and update real time.  This would get the telescope through the night with little impact to observations.  Incidentally, to get back to standard operating mode, the observer would once again type h1 to enable feedback associated with HP1, then type cn to return to normal operations.

Telescope is currently being slewed about to test the integrity of the readouts, particularly HP1.

The observer will note that the airbag control computer has been swapped, as has the keyboard.