Slightly modified and reposted to apo35-dis: For those interested in the 3.5m Guider performance, I'd like to expand a little on last night's nightly log: Don Hoard was observing radial velocities of a close binary with DIS in high-res mode. Since he was to be sitting on one object for a long time, this made for an ideal guiding test. After slewing to the object, we rotated to an InstAng=+30 in order to put a suitable guide star (whose position was known to be appropriate before observations began) in the Guider field of view. The object was a 14.1 magnitude HST GSC star. Because the DIS instrument block appears not to be correct, some jockeying was required to get the target in the slit and the guide star in the Guider FOV. With the red filter we got 77,000 counts in 10 seconds. Guiding was started and continued for 3 hours and 40 minutes. Guiding was halted at that point when the target reached 3.3 airmasses, although the Guider was still working fine. The flux level of the 5-minute spectra obtained over the 3:40 hours indicates that the star stayed in the slit the whole time. Note that while we were close to full moon, sky background was minimal. I measured a S/N for the star (before guiding began) of ~150. With dark subtraction, it would be ~230. Again, from the image before guiding began, the star had 77,000 total counts, and a FWHM of 1.75'' and a peak of 3900 counts (10 second exposure). The time interval between the close and open of the shutter during guiding appears to be 3 seconds. I do believe that this was the first guided science observation. Before routine guiding can begin, problems with the DIS instrument block and the Guider filter wheel must be resolved. I haven't finished analyzing the logged data yet; I should have more after that is done. It will be posted at http://www.astro.washington.edu/deutsch/apoinfo/guider/guider.html where all the other current information I have is stored. Eric ---------------------------------------------------------------------------- Eric Deutsch email: deutsch@astro.washington.edu Department of Astronomy Voice: (206) 616-2788 University of Washington FAX: (206) 685-0403 Box 351580 WWW: http://www.astro.washington.edu/deutsch Seattle, WA 98195-1580 Physics/Astronomy Bldg., Room B356F APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 6 in the apo35-dis archive. You can find APO the archive on http://astro.princeton.edu:82/apo35-dis/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-dis@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO