Troubleshooting guide

pointing coordinates, and dither about that new position. See the next section on offseting the telescope from
the FLAMINGOS command line.
You can monitor seeing variations and any focus drift if you continuously use fwscan while the dither pattern
executes; just start using it after the first two images have read out.
F. Offseting the Telescope from Flamingos1a
At certain times (such as pointing checks or adjusting the position of your sources on the detector) you may
wish to offset the telscope directly from flamingos1a rather than having your operator do it. To do so use the
following commands:
offset.kpno.pl <RA> <Dec> - Offsets of the telscope in a absolute sense with respect to the
pointing center (where the telescope offsets are (0, 0)). Offsets are in arcseconds and positive values
move the telescope East and North from the pointing center where the offsets are 0, 0. For example,
offset.kpno.pl 5 10 will set the telescope pointing 5 arcseconds East, and 10 arcseconds North.
Repeating this command with the same offsets will not move the telescope.
relative.offset.kpno.pl <RA> <Dec> - Offsets of the telescope relative to wherever the
telescope presently is pointed. Offsets are in arcseconds and positve values move the telescope East
and North from the telescope's current position. In this case, relative.offset.kpno.pl 5 10
will move the telescope 5 arcseonds East and 10 arcseconds North. If the offsets initially were (0, 0)
then after this move they will be (5, 10); repeating this command will move the telescope and the new
net offsets will be (10, 20) arcseconds.
Typing offset.kpno.pl 0 0 will send the telescope back to the starting pointing center.
Typing clear.offsets.kpno.pl will allow you to define the present net pointing (base plus offsets) as the
pointing center. It will cause the telescope to absorb the present offsets, i.e., the offsets on the TCS will reset to
(0, 0) but the telescope will not move.
G. Taking Darks
Darks need to be taken at every exposure time that was used for observation on the sky. Generally 10 – 20
images are taken per exposure time, for averaging; they are usually taken sometime during the daytime. To take
a single set of images at the same exposure time, use the script
more.singleimages.pl <number of images desired>
If the required darks have a long exposure time, consider starting them going as you walk out the door to go to
bed. Be very certain to check on the quality of the data once you get up—the array controller may hang midway
through the data set, or have a glitch which affects some of the images.
If you need to take many darks at several different exposure times, consider writing a cshell (csh) script which
consecutively calls config.exposure.pl and more.singleimages.pl multiple times, each time passing
the proper keystrokes into each script. An example, based on a script written by Anthony Gonzalez (UF),
appears in
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