If you take dome flats in the morning after your observing night, be sure to use the commands endnight to put NIRC2 into safe mode and aohatch close to protect the adaptive optics bench when you are finished.

You can obtain at least broad-band flat fields by using the dome flat lamps designed for the optical instruments. Ask the OA to point to a good flat field spot on the dome (usually at an elevation of 45°) and turn on the spectroscopic lamps. These are the bright lamps. Below is a table of exposure time estimates that should produce 8000 DN or somewhat less in each broadband filter and camera combination. Numbers in parantheses indicate that the exposure time is to short to reach with the full frame. Either a subarray can be used, or you can try using a flat field from the narrow camera to calibrate data taken with the wide or medium camera. Note that this technique has NOT been tested; it is only a suggestion.

Note also that there are two flat field lamps. If you see only 1/2 of the expected flux, there may be a burned out lamp. Ask the OA to check by looking for uneven illumination on the dome.

1. In any waikoko xterm type 'configAOforFlats' and answer Y to the prompt (if you have checked beforehand with your support astronomer).
2. Bring up the dome lamp control gui found under 'interface subcomponents' on the pulldown.
3. Turn on the SPEC lamps and confirm that you see flux on the AO WFS (and that OFF results in very little flux on the AO WFS). If this check doesn't work out, check the light path (e.g., OFM in SC gui, Tertiary position, etc)
4. Manually take the flats using the recommended times in the table below, or run a script (e.g., /home/nirc2eng/vis/arc/flat_examples/makeFlats)
5. If it's morning, follow the caution at the top of this page (endnight and aohatch close).

Estimated exposure times in seconds for NIRC-2 dome flats.