The following excerpt from the 12/26/99 3.5m log is worthy of note as it shows the best image FWHM ever reported for the telescope (previous best was about 0,7"), presumably due to the replacement of the secondary. The new secondary was first employed for science observations only on 17 December, and the telescope optical collimation has not yet had its final fine tuning using the new Shack-Hartmann instrumentation, so there is no reason to think that these numbers represent the best we will be able to achieve. However, they certainly provide strong evidence that the hard work of many people involved in our image quality campaign and the generous support of the ARC institutions (the new secondary was the single most expensive item among the Three Year Plan projects) are paying off in a major way. Ed Turner >The night was clear and warmer than recent weeks, with exceptionally >good seeing. Some of the numbers in the focus log below are actually >an overestimate of the seeing, since we were undersampled with GRIM at >f/5. The telescope was getting considerably better seeing (at least >in the infrared) than the DIMM monitor. > >... > > FOCUS LOG > DECEMBER 26 1999 > Wind >Time Inst Focus Az El #Temp Dir MPH filt FWHM " >17:35 GrIm2 0(1016) 119 45 0.6/3.3 152 11 J 1.1 >19:05 GrIm2 0(846) 147 59 1.2/1.0 177 10 J 0.76 >23:15 GrIm2 +50(855) 253 74 1.6/1.1 226 9 K 0.52 >01:35 GRIM(f/10) +10(789) 191 77 1.7/1.1 276 10 H 0.57 >02:20 GRIM(f/5) -50(838) 194 46 1.0/0.7 293 11 J 0.84 >#First temp is air, second temp is telescope. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 408 in the apo35-general archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-general/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-general@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO