Troubleshooting guide

The images are usually kept in /data/4mguest/Maskfiles/.
Flip and rotate until the image WCS matches that of a raw FLAMINGOS frame.
Turn on tiling, with a vertical orientation; tiling of buffers 1, 2, and 3 is useful. Hide buffer 4.
5. Acquire target on FLAMINGOS in K
s
filter.
Set exposure time to pick out aligment targets. Try an exposure time of 10 – 30 seconds if they are
bright, but do not let them saturate. You may need to use much longer itimes (60 – 120 seconds) if
they are very faint.
Attempt to visually pick out the alignment targets (stars or galaxies).
If necessary, adjust telescope pointing with relative.offset.pl until the targets are within the
central region of the array.
If targets are faint, you may need to offset a small amount (20 arcsec) and work on a difference
image. See the comments at the end of this section on how best to do this. Integration times may need
to be increased, too.
6. Have the telescope operator adjust focus on the TV camera,
The guide camera should be confocal with FLAMINGOS, and should give a good starting focus.
Next, take a series of images with FLAMINGOS over a range that covers best focus, offsetting the
telescope between each image; use relative.offset.kpno.pl and dither back and forth by 10 –
20 arcseconds. Run fwscan on the stack of images to determine which focus setting was best (cf. III.
Nightly Startup Tasks, §B − Startup on the Sky).
Don't spend very long on this, as the focus will change.
Record the middle dome temperature.
7. Have the telescope operator acquire a guide star and start guiding.
Verify that the guide probe radius is greater than 100 mm, in order to avoid vignetting.
8. Insert the decker MOS baffle using config.filter.grism.decker.wheels.pl.
9. Verify the decker is straight (check the edge of the decker MOS baffle); use tweak.decker.pl if
necessary (cf. the previous section on long slit alignment).
10.Measure the star centroids and write them to a stars file for xbox:
imexam logf=stars keep+
Type a on each star
11.Insert MOS plate using config.mos.wheel.pl.
12.Check the plate is straight on the array with by stretching the display to see the plate frames. If it looks
noticably unstraight, use a ds9 ruler to estimate the offset angle and adjust it with use tweak.mos.pl
(cf. the previous section on long slit alignment).
13.Measure the box centers and write them to a box file for xbox. Measure the boxes in the same order
as you measured the stars.
imexam logf=box1 keep+
type e to generate a contour map
type g to get the graphics cursor
center the cursor on the box and type x
type i to return the image, and repeat this process for the other boxes.
If you cannot see the box well in the contour plot, consider starting over after setting the upper contour
limit threshold to ~5,000 ADU; use epar eimexam and change the upper limit from the default value
of indef.
14.Run xbox:
Type epar xbox
Set the parameter image to the most recent mask image
Set the parameter input = box1(the log filename you used in imexam)
Set the parameter stars = stars (the log filenames you used in imexam)
FLAMINGOS@4-m, Ver. 2.34, 2006 Apr 04 Page 26 of 44