Dec 28 (UT)

01:01 Slewing to the evening telluric star HIP13917.

- Outside temp dropping fast (outside temp = -11.1, mirror = -8.9 → ΔT = 2.2 C)

- Having a problem with the mirror control system (actuators) presumably due to a cold temperature.

- Slewing to the zenith and trying there.

- Repeated mirror panics at low elevations due to low air pressure in some actuators (45 deg or less).

01:52 Engineers called.

02:05 Engineer on-site went out into the dorm to listen to air leak while the telescope is stowed at zenith.

02:50 Air leak is likely the cause. SX air pressure rising abnormally (blue line?) at lower alititude.

03:50 Air pressure was completely lost even at the zenith, so that's it for tonight...

-- %USERSIG{EiichiEgami - 2014-12-27}%

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