Logging Guider "Guide Box" Images
(using glogon and glogoff)


HOW TO GLOG


Glogon and glogoff toggle logging of the guider's "guide box." Issuing the glogon command causes header information and the
pixel values of ALL subsequent guide boxes to be saved, as ascii text, to a file named "guidebox.log", in the "nightpath" directory: `nightpath`guidebox.log. Logging continues until the operator enters the glogoff command.

Glogoff discontinues logging and moves the previously collected log file. Glogoff takes as an optional command line argument
the name of the file to which the log will be renamed. For example


% glogoff lris_slit.1


would terminate guide box logging and move the log file from `nightpath`guidebox.log to `nightpath`lris_slit.1 If the operator does not supply a file name, then the log file is moved to `nightpath`guidebox. That is,


% glogoff


would terminate guide box logging and move the log file from `nightpath`guidebox.log to `nightpath`guidebox.

NOTES

  1. The glog files can become quite large. Care should be taken to ascertain that sufficient space is available for the intended logging operation and that logging is turned off when no longer needed.

  2. If the operator does not supply a file name with glogoff, then the file `nightpath`guidebox, if it exists, will be overwritten. I recommend providing a descriptive file name argument, and will happily change the glogoff script to enforce this requirement, if so desired.

  3. The command scripts themselves are only a few lines long and you can easily satisfy your curiosity as to their innards through inspection. The logging scheme is actually carried out by the guider itself. At a point in each guide cycle, the guider tests for the existence of the magic file `nightpath`guidebox.log If that file is there, the guider writes the log info to it; otherwise, not. So the scripts really just signal the guider through the file system.

  4. There are rudimentary (IDL) tools to look at the logged data. Shui Kwok is now the keeper of this flame, though I will be happy to show you what (little) there is.Let me know if there is anything else you would like to know about this scheme.

John Gathright