(Robert Lupton mentioned to me that this message may have gotten lost, so here it is again) This evening I ran some tests with the new mirella and Remark software that handles grating changes (now that we have three sets of gratings). I have tested the software with the low and high resolution gratings, I haven't yet tested it with the medium resolution gratings. The Remark and mirella software both appear to work as advertised. However, the central wavelength of the red high resolution grating is 45 A short and that of the blue high resolution grating is 95 A short. I think this is due to the non-repeatability of the grating positions in the turret after the gratings have been swapped in and out. In previous tests, I found that these values change each time the gratings are taken out. If the medium resolution grating is to be used on a regular basis, the observing specialist needs to be able to edit the value of the step position of the zero order spectrum for each grating, because this will need to be recalibrated after each grating change. I estimate a grating change should take about 20 minutes and the recalibration should take an additional 20 minutes. - Karen G. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 48 in the apo35-dis archive. You can find APO the archive on http://www.astro.princeton.edu/APO/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