Hi all, I'm reducing JHK imaging data taken with GRIM, in Feb '01. I'd appreciate advice from anyone who has reduced them in the near past. I'm interested in the following: 1) I used the "obj4" script to do the sky/object/sky chopping. Are the offsets quoted in the FITS header (as X and Y) accurate enough to be used for aligning the images? 2) Does anyone have bad pixel masks and flats (in J,H and K) constructed recently? I've constructed these and I'd like to compare them with earlier ones to see if they are stable. 3) I'm setting the Gain=4.7 electrons/ADU and readnoise=110 electrons, as quoted in the GRIM manual (written in 1997). Has there been any recent measurements of these quantities? 4) if you have scripts to shift/coadd the images obtained in the "obj4" pattern, that'd be much appreciated. Thanks, -- Vijay APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 46 in the apo35-grim archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-grim/INDEX.html APO To join/leave the list, send mail to apo35-request@astro.princeton.edu APO To post a message, mail it to apo35-grim@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO