Some notes on how to avoid and cope with Arcon crashes.

A known issue with the Mosaic II Arcon are occasional "freezes" or crashes which may require a restart of some or all of the system with a concommitant loss of observing time. These can be avoided or ameliorated through the following practises:

  • Do not use the Mosaic II observing computer (ctioa8) for anything except observations
    Any data reduction, ftp-ing, script editting, web browsing or emailing should be done using another machine in the control room, such as ctiozm, ctioa7, or ctio4m.
  • Don't edit scripts while they are running!
  • It is possible that the Arcon software may develop problems communicating with the telescope control system (router), particularly in trying to set the focus at the beginning of an exposure. If this is the case, a reboot may not be required. Ask your observer support staff to verify TCS communications, set the telescope focus manually, then use the GUI to tell the Arcon software where the focus is.
  • Do not use the "abort" command as this does not always function correctly. Instead, if you wish to terminate an exposure early, use the tchange command with a negative time interval to shorten the exposure time appropriately and force a graceful end to the exposure.
  • mosdither is known to feature increasing delays between exposures in a dither sequence. Use the mosocs facility instead.
  • Should you lose one or more of the Arcon interface windows in the VNC window containing the IRAF interface, but not that containing the IRAF command line itself, you can restart the interface without restarting Arcon by typing "gwcclose" then "gwcopen" at the IRAF prompt.

    • Page created: 7 November 2006 by Tim Abbott

    Staff Contacts:
    Tim Abbott: tabbott@noao.edu
    Alistair Walker: awalker@noao.edu
    Chris Smith: csmith@noao.edu
    Armin Rest: arest@noao.edu