Hello all, We plan to make a small change in the default wavelength center for the DIS R300 grating, from 7600 Angstroms to 7500. For the reddest targets, the red-side spectrum just about fills the chip with not a lot of room to spare; this change should ensure that we get better coverage of the blue end around the dichroic cutoff, while still allowing spectra to reach SIII 9530. As always, any user may still request 7600 (or any other red wavelength) as their center if preferred. This change will only affect users who request the default center. If you have requested the default center in the past and you care more about the red end of the spectrum than the dichroic overlap, or if it's important to you for future data to match past data as closely as possible, feel free to explicitly request spectra centered on 7600 instead of the new default. For reference, the default center for the B400 grating, which is usually used in tandem with the R300, is 4400 Angstroms -- this should allow full coverage from the dichroic to the blue cutoff with room to spare. The R1200 and B1200 gratings do not offer full spectral coverage, and so the choice of wavelength center is more specific to the desired science; however, the defaults for those gratings are 7300 and 4400 Angstroms, respectively. Russet McMillan. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 1064 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