Troubleshooting guide

We usually use only sky lines (OH) for wavelength calibration in the HK-band.
If you wish to resume guiding on the science target for additional observations without rechecking the alignment
(this may or may not work):
1. Have the telescope operator do the following:
Turn off calibration lamps.
Take out the Comps mirror (put it back to the THRU position).
Resume guiding. N.B.:
When guiding is suspended the guide star may move slightly out of the guide box.
Make certain the telescope operator DOES NOT WARP the guide box onto the star to resume
guiding. Doing so will move the guide box to the star's present location, and the telescope will be
guiding at the wrong place, i.e., your target will no longer be optimally aligned on the slit.
If the star has moved out of the guide box, the telescope operator should:
Leave the OFF button pushed on the GUI.
Tweak the telescope pointing with the hand paddle to move the star into the guide box.
Once the star is in the box, resume guiding by pushing the LOCK button on the GUI.
Once the star is again in the guide box, wait a minute to watch the guide software capture the star's
location, and move it back to the guiding center within the guide box.
2. Take a junk image.
To obtain dome flats, position the telescope at the HA midpoint of the target observation (as for the quartz flats).
1. Have the telescope operator do the following:
Turn off telescope tracking and position the telescope at the HA midpoint of the target observation.
Turn off dome tracking
Manually move the dome so that it completely blocks the telescope aperture
Turn on the flatfield projector on the telescope using the Bright lamps at maximum setting
2. Set filename and exposure time. Use config.exposure.pl.
Integration times of 10 - 30 seconds should suffice for JH-band and HK-band spectroscopy.
Take a test exposure (singleimage.pl). The counts should be <25,000 ADU for wavelengths
< 2.4 microns.
With 30 second itimes, it is possible to do 8 reads, if you can accept the little bit of extra overhead.
3. Take 5 flats with the lamps on. Use more.single.images.pl 5.
4. Have the telescope operator turn down the flatfield lamp, or turn it off.
Flats at two different illumination levels can be differenced to remove the dark current.
5. Take 5 flats with the lamps off. Use more.single.images.pl 5.
FLAMINGOS@4-m, Ver. 2.34, 2006 Apr 04 Page 30 of 44