idlpacman

We have a license for one run-time idl process per telescope control computer, so we have constructed an idl data analysis program that can run with no command-line input. This program takes the source lists that are output by SExtractor (sobj files) and calibrate them against the USNO A2.0 catalogue, producing calibrated object lists. These lists, along with the corrected image headers and the _sky files, are saved into FITS files called cobj files. The idlpacman function is activated through the following command:

prompt%$>$ echo idlpacman | idl

This command has been defined into an alias called startidlpac (See also Section 2.3.3), which also pipes the output into a log file called idlpac.log, which can be inspected to monitor the program's activity. idlpacman looks for a configuration file in the current working directory. (See Section A.6 for the standard directories for realtime operations.) This file must be called idlpac.conf. This file contains the names of the files and directories in which idlpacman will find its input and write its output. Here is an example of a potential idlpac.conf file (the format does not support comments in the file):

The parameters do not have to be in this order, but they must all be present. sobjlist is the output file from sexpacman.pl that contains a list of the sobj files to be processed by idlpacman. workdir is the working directory for the process (might be, but not necessarily, the directory from which is was called, which is where idlpac.conf should be). sobjdir is the directory whence the sobj files are read, and cobjdir is the directory where the cobj files are written. imgdir is where the original corrected images are stored.

The last two elements enable us to monitor the analysis status and image quality in near real time. Within the statdir, a file called ``[statroot]_run.dat'' is created that keeps a running log of various diagnostic quanities: the image name, the time, the temperature, the difference between the catalog and ROTSE-III positions of stars, the FWHM of the PSF, the elevation of the pointing direction, and the limiting magnitude of the image. Four of these quantities are also graphed in a GIF image named status_mon.gif, which is regularly transferred to Michigan for display over the WWW (Section 8.4.2). Such an image is displayed in Figure 8.3. The log file is also used by the mount in its homing operation, see Section 3.8.

Figure 8.3: Four status variables are displayed graphically for near-real-time viewing over the WWW. Clockwise from top left: the median FWHM as a function of temperature, the image limiting magnitude as a function of time, the median FWHM as a function of elevation, and the pointing offset between mount and true coordinates. In the bottom figures, the most recent data point is plotted in red. These graphs help us determine when problems arise during the night, as might be evidenced by a drift in the pointing accuracy or a dramatic change in the limiting magnitude (which usually indicates clouds).