> our 3.4m aperture to 2.6m. The camera on the 2.2m had an optimized > cold stop that blocks out the high emissivity central hole in the > primary; I don't know if GRIM II does. GRIM II does not. Cold stop only blocks at outer edge of primary/secondary image: no rotating vanes or central obscuration in mask. Interesting measurements all 'round, though. - mh APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 36 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