Troubleshooting guide
The following commands are used for long slit and MOS plate spectroscopy:
On the Flamingos command line:
config.exposure.pl Set up the filename and exposure time.
config.filter.grism.decker.wheels.pl Set up and move Filter or Decker wheels.
config.rel.mv.filter.grism.decker. Execute relative motion of Filter, Grism, or Decker wheel
 wheels.pl
config.rel.mv.mos.wheel.pl Insert long slit or MOS plate slit.
config.mos.dither.kp2m.pl Set up the spectroscopy ABBA parameters.
dither.mos.nonudge.kp2m.pl Take spectroscopic data in the ABBA pattern.
guide.define.abba.manual.beams.kp2m.pl Set lock positions for the A and B beams.
guide.define.slit.center.manual.kp2m.pl Set lock position 1.
guide.mos.offset.kp2m.pl Make guided relative telescope offsets.
set.bias.pl Change bias for imaging or spectroscopy.
tweak.decker.pl <delta_angle> Adjust the Decker wheel position by angular increment.
tweak.mos.pl <delta_angle> Adjust the MOS wheel position by angular increment.
At the iraf cl prompt:
imexam Measure slit profiles and stellar centers (keys: a, r, j, k, x, g, i).
B. Preliminary Setup
Our experience with FLAMINGOS leads us to note that the efficiency of setting up on targets for spectroscopy 
can be significantly improved by carrying out some preliminary work during the afternoon or at the beginning of 
a spectroscopic run. Unlike an optical spectrograph, FLAMINGOS has no facility for viewing the field on the 
slit, and target acquisition must be carried out by imaging through the slit onto the science array. Fortunately, 
the motions of the Decker and MOS wheels appears to be quite reproducible, and the relative motion scripts 
incorporate backlash removal, so it is possible to measure the location of the slit apertures on the array prior to 
observing and move the target to the appropriate detector coordinates, and then move the slit into the beam with 
confidence that it will be close enough to be centered up. This strategy greatly reduces the number of time-
consuming wheel motions.
• During the afternoon, after the masks are loaded, the support astronomer should check the orientation 
of the masks with respect to the columns of the array by taking images in the Ks filter and tweak the 
zero point of the MOS wheel motion using the ufmotor commands until the masks are precisely aligned 
with the columns of the array. The mask stepper motor positions are sufficiently accurate so that 
alignment of one mask should result in the other masks being aligned to within 3 – 4 pixels over their 
length.
• Once this is done, the support astronomer or the observer should cycle through the masks and measure 
the [x,y] position on the array of the center of the alignment hole and/or the center of the long slit and 
note these positions. This will save a lot of time during the night.
• If doing spectroscopy with one of the long slits in the MOS wheel (not one of the masks), move the 
Decker wheel to the slit position and use the command tweak.decker.pl so that the image of the decker 
aperture is centered on the location of the slit which will be used for spectroscopy.
• If one is doing spectroscopy with one of the slit masks mounted in a MOS mask position, set the 
Decker wheel to the mos position. The 6 × 20 arcmin field is adequate for initial acquisition, and it is 
not necessary to move this wheel during the night.
FLAMINGOS@2.1-m, Ver. 2.39, 2011 May 13 Page 26 of 46










