-- JoshuaWilliams - 30 Apr 2020

Raise Primary Mirrors / Recovering from Primary Mirror Panic

Auth: Josh Williams
v1.0 April 29th, 2020

**You’ll first want to bring the telescope to zenith prior to raising a mirror.**

**Do NOT try to raise the primary mirrors while telescope is at horizon.**

(The mirror can raise at any elevation, but cannot raise while the elevation is changing. It is faster to raise the mirror while parked at zenith.)

If raising the M1 due to a mirror panic, in the appropriate (Left/Right) Primary Mirror Cell GUI (PMCL/PMCR), first click on Recover Panic. Click on All Air On to start raising air pressure.

While air pressure is being raised, in the PMCL/PMCR GUI, click on Air Pressure to bring up the PMC Air Loops Status and Control subGUI.

From PMC Air Loops Status and Control subGUI, you should keep an eye on all air loops (Blue-1, Green-2, etc.), until they reach a value between 100 & 120.

Once the air loop values are stable between 100 & 120, from the PMCL/PMCR GUI, click on Auto-Raise to start raising the primary mirror again, then click on Hardpoints to bring up the Hardpoints Status and Control subGUI.

From the Hardpoints Status and Control subGUI, you should keep an eye on the load cell values, as they go from >500 to ~0, and eventually the limits all read “OK”.

While the mirror is being raised, from PMCL/PMCR, click on Actuators to bring up the Actuators Status and Control subGUI.

From the PMC Actuators Status and Control subGUI, click on Enable All to enable all actuators. You should see all disabled actuators in the “Disabled” box eventually disappear.

From the PMCL/PMCR GUI, you should watch the weight return to 100%, and Chase state become “Idle”.

If a mirror panic happens during night observations, in the PMCL/PMCR GUI, click on Collimate. This isn’t necessary, but it can save time. The primary mirror is now ready.

Tips & tricks

If the air pressure doesn’t want to come on when you first press All Air On in PMCL/PMCR, you can check the status of the air compressors (AC) from Environmental Control Subsystem GUI (ECS) to make sure they’re on.

Lowering Primary Mirrors

In the (Left/Right) Primary Mirror Cell GUI, click on Auto-Lower.

1. Wait for 0% in Weight section and “Auto-lower complete” in log.
2. In Air Control section, click on All Air Off.
3. Wait for “Complete” message in log.