Simple User's Guide to running the OSS subsystem

The OSS GUI is not normally needed by observers since the PSF GUI shows the M2 hexpod position information. The M2 coordinates are normally entered through the PSF secondary page, so these hexapod commands are more than you need to know. (This is really a guide for the telescope operator.)

Starting the OSS GUI

ssh into one of the obs computers.

type 'OSSGUI &'

if the subsystem isn't running (GUI all red), have the TO start the OSS subsystem.

  • Click on one of the Secondary Mirror icons on the top left or right on the main OSS GUI to get a secondary mirror form.
  • Click on one of the Tertiary Mirror icons on the middle left or right on the main OSS GUI to get a tertiary mirror form.


  • If the position numbers from the M2 hexapod suddenly go crazy (more or less random numbers), this is a sign that you need the TO to stop and restart the OSS subsystem (should not happen now - Oct 2015).

  • To check if a UMAC is alive, send the harmless command that queries for the version number of the software:
    • Type 'ver' in the 'Send Cmd' box, then click the 'Send Cmd' button (or just hit return).

  • If OSSGUI is reporting "RPC Error", you probably need the TO to stop and restart the MCSPU.

  • Stop and restart the OSS using the TCSGUI if nothing else works.

Rebooting the UMAC (when all else fails)

On the Secondary Mirror or Tertiary MIrror engineering interface OSS sub-gui:

  • Type '$$$' in the 'Send Cmd' box, then click the 'Send Cmd' button (or press return). (this is the reboot signal for UMAC)

  • Clear '$$$' from the 'Send Cmd' box, so you don't hit it accidentally later.

  • After the reboot is done, the mirror must be homed.
    • Secondary - click the 'Init' button and wait for command complete.
    • Tertiary - click the "Init' button and when command is complete click 'Home MIrror', wait for command complete, then click 'Home Sel'.

Tertiary Mirror

The IP address for the remote power switch of the M3 UMACs is (Oct 2015). See the Engineering Wiki for instructions on how to use it.
The IP addresses for the tertiary mirror UMACs are (left) and (right).

Secondary Mirror

The IP addresses for the secondary mirror UMACs are (left) and (right).

-- JohnHill - 14 Apr 2008, Revised 17 Apr 2008
Topic revision: r10 - 28 Oct 2015, ChrisBiddick
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