The Curtis Schmidt continues to fill a unique niche at CTIO, offering an extremely wide fieldofview with good sensitivity. Changes in the CCD plans for the Hydra spectrograph (see Hydra article) mean that the SITe 2K #5 CCD will remain on the Schmidt for the foreseeable future, providing excellent image quality over a 1.3 × 1.3 degree field, albeit with the 2.3" pixels producing very under sampled images (typical FWHMs of 1.1 to 1.2 pixels). The SITe 2K #5 is a thinned, backside illuminated CCD, providing a quantum efficiency curve similar to the other SITe (or Tek) CCDs at CTIO. It only has two good amplifiers, but recent modifications in the Arcon control software have sped up the readout to about 38 seconds at the default gain (there are 4 gain settings available, from 2.7 e/ADU down to 0.6 e/ADU). The users' manual (available at http://www.ctio.noao.edu/cs/c-s.html) has been updated to reflect these changes, as well as changes to the IRAF/Arcon acquisition software.
For studies of extended or low surface brightness objects, the combination of the Curtis Schmidt with the SITe 2K CCD is competitive with telescopes such as the KPNO 0.9m+Mosaic in the north. Its wide field, deep imaging capability and low subscription rate make it an ideal instrument for surveys or larger projects for which it might be difficult to obtain enough time on the larger telescopes.
Chris Smith csmith@noao.edu