6.4 Calibration

6.4.10 NIRC-II


6.4.10.1 Measurement of field-dependent errors in the NIRC-II image.

(This calibration will be performed infrequently). When the image is sharpened for the center of the 10-arcsecond field of view of NIRC-II, there still may be some errors off the center. It is very likely that these effects will be totally dominated by uncorrected seeing on-axis, and anisoplanatism in the corrected field. If it is necessary, we can measure the field dependent errors due to the AO system. This can then be supplemented by modeled our measured field-dependent errors of Keck-II.

6.4.10.2 Flat-fielding of the CCD in NIRC-II (This calibration will be performed frequently.)

Step 1. NIRC-II will send the command to do flat fielding.

Step 2. Make sure that the telescope simulator fold mirror(SFM) is removed, that the acquisition camera fold mirror (AFM) is removed, and that all servo control loops are open. The AO system will stay in an open-loop state until the flat-fielding is completed.

Step 3. NIRC2 will move the telescope to dark sky, (TBD).

Step 4. NIRC2 will notify the UISC when the flat-fielding is completed.

6.4.10.3 Calibration of spectrograph. (This calibration will be performed frequently).

The current thinking is that NIRC-II will have several calibration lamps that will share a translation stage with the telescope simulator fold mirror. The lamps will shine onto a brushed aluminum plate that is near the focus. It is assumed that NIRC-II will be responsible for powering the lamps on and off.

Step 1. NIRC-II will send a request for calibration of the spectrograph.

Step 2. Insert the aluminum blank.

Step 3. When NIRC-II is finished, remove the aluminum blank.

6.4.10.1 - Measurement of field-dependent errors in the NIRC-II image.
6.4.10.2 - Flat-fielding of the CCD in NIRC-II (This calibration will be performed frequently.)
6.4.10.3 - Calibration of spectrograph. (This calibration will be performed frequently).

AO Software Design Book - 25 FEB 1997

Generated with Harlequin WebMaker

Back to the Keck Home Page
Back to the Keck AO Page