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CTIO Instrumentation News (1Jun95) (from CTIO, NOAO Newsletter No. 42, June 1995) During the past quarter we completed a number of upgrades that directly improve the observational capability at the telescopes. Two new CCDs were commissioned: the Loral 3K X 1K on the 4-m R-C spectrograph and the STIS 2K X 2K on the Schmidt (see accompanying article). The Infrared Spectrometer now has a cross-dispersed mode well suited for multi-band spectroscopy of faint objects, although the efficiency is somewhat lower than originally hoped. There has also been a significant improvement in the image quality at the 0.9-m telescope, following the installation of extractor fans at the bottom of the enclosed telescope tube (copying what was done on the Las Campanas 1-m; see accompanying article). In addition, the fibers of the Argus multiobject spectrograph can be positioned to higher accuracy than was previously possible, as the result of a recalibration of their mechanical motions using a new measuring device. The two visiting astronomers who have since used Argus report that it is now capable of blind pointing, with no need to recenter the fibers visually. A site-seeing monitor is now working on Cerro Tololo. It consists of a Las Campanas seeing monitor (generously furnished by Carnegie Observatories) on top of a tower next to the 16-inch dome. There had been a long hold-up installing this system because of lack of a suitable telescope mount, but one has now been generously provided to us by SAO. The system measures image motion and then converts it to estimated image diameters using standard Kolmogorov theory. It will track stars on its own for 2-3 hours at a time, so we plan to run it for several hours every night. During the first three nights it was tested we recorded 0.45", 0.65" and 0.35" FWHM for the site seeing. On the third of those nights we recorded 0.65" FWHM at the 4-m f/8 focus. Some less obvious improvements around the observatory are the completion of three additional CCD dewars, the replacement of the La Serena-Cerro Tololo microwave link with a more reliable system, and the completion of a project to adapt a commercial high-speed video board for use with our CCD TVs. A very worrying occurrence during this period was a fire at the 4-m telescope, in the pre-dawn hours of March 10. It occurred at the rear of the telescope in an area occupied by the primary mirror cooling system, and was fortunately extinguished (mostly by Mauricio Fernandez, the night assistant) before any major damage was done. Fernandez and the observers (Malcolm Smith and Richard Elston) noted a serious deterioration in the seeing (!!) as well as strange noises over the intercom, and went upstairs to investigate. They were greeted by rather spectacular flames in the room containing the mirror cooler and the RA drives, which they were quickly able to control. The telescope was back on the air the following night. The mirror cooling system involves a heat exchanger that uses glycol from the floor chilling system. There had been a major leak a few days before, which we had believed was thoroughly cleaned up. However, there was some exposed styrofoam insulation in the area that had become highly flammable after being soaked with glycol. It apparently ignited due to heating by a partially shorted electrical circuit in an adjacent outlet box. We are now working on improving the alarm systems and removing exposed styrofoam and other fire hazards from the telescope building. Jack Baldwin (jbaldwin@noao.edu)
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