Troubleshooting guide

C. Long Slit or MOS Plate Alignment
1. Set instrument PA before acquiring target.
• This must be done first, as the telescope must be at zenith in order to move the rotator.
• For safety reasons, the telescope operator must make the rotation from the Cassegrain Cage.
• Run config.mos.dither.kp4m.pl, and set the parameter ROT_PA to the new value, so the WCS compass
arrows will display correctly in ds9 and the dither motion will be in the correct direction
2. [MOS]Load image of science field. The observer should be able to display an image of the science field
(DSS, 2MASS) on a ds9 display on their laptop, with the appropriate region mask overlaid. This makes it
much easier to directly compare the image of the field on FLAMINGOS with the DSS field without having
to switch between buffers on the FLAMINGOS display or look at small fields in tile display.
3. Have telescope operator verify pointing on the North Port TV Camera.
• Acquisition can be done with the Decker wheel in mos, MOS wheel in imaging, Filter wheel in H, and
Grism wheel in open1. If doing HK spectroscopy, acquiring in JH or H gives lower sky background.
• Acquire a SAO star near the science field.
• There should be a grease pencil mark on the TV monitor indicating the telescope pointing.
• Take a quick image (2-5 seconds), and make certain the SAO star is well centered on the array. If is
not, center the star with relative.offset.kpno.pl, then take another image. Once it is well centered, have
the operator Z the telescope pointing (cf. § III.B. Nightly Startup Tasks: Startup on the Sky)
4. Acquire target. Once the telescope is at the science field, have the telescope operator locate a guide star
and begin guiding; verify that the radius of the guide probe is > 100 mm to avoid vignetting.
5. Take an image of the field. Use an integration time ~ 10 s so that the field is identifiable and the target or
alignment stars can be easily located.
6. Identify the field.
• Comparing the FLAMINGOS image with that on the laptop, identify the alignment stars, particularly
the one which goes into the large box on the mask.
• If doing long slit spectroscopy, identify the science target.
• Measure the [x,y] position of the alignment star or target on the FLAMINGOS image using imexam,
key a.
• Using the ds9 ruler or a calculator, calculate the distance between the [x,y] position of the alignment
star and that of the alignment box or long slit center measured earlier
• Offset the telescope with relative.offset.pl δRA δDec (or have the telescope operator do it) by the
calculated distance. The telescope must be guiding.
• Take another image and verify that the alignment star is at the [x,y] position of the box or slit.
7. Check the telescope focus and readjust if necessary.
8. [MOS wheel long slit] Move Decker wheel to slit using config.rel.mv.filter.grism.decker.wheels.pl
• Verify the position and alignment of the slit decker measured previously.
• If necessary, use tweak.decker.pl to align slit decker to the correct location.
• Move long slit into beam using config.rel.mv.mos.wheel.pl
• Take an image and verify that slit is in the position measured previously. If so, one should see
the target at least partly in the slit.
• Use relative.offset.kpno.pl or ask the telescope operator move the telescope to center the star on
the slit
FLAMINGOS@4-m, Ver. 2.39, 2013 April 23 Page 26 of 47