Bruce Bohannan, Richard Green, and Tony Abraham
Because the summer months of July and August are traditionally monsoon time, with cloudy skies and thunderstorms, KPNO shuts down to pursue a variety of improvement and large-scale maintenance projects. Major activity this summer includes aluminization of the WIYN primary mirror and work on two key improvement projects on the Mayall.
The WIYN primary will receive a fresh coating of aluminum (it was last aluminized in 1998). After the mirror is re-installed, the optics will be collimated and new active optics lookup tables constructed. The latter steps are key to achieving excellent optical performance from the telescope. All of the seeing-related improvement projects at the Mayall have combined with regular optical tune-ups to yield average seeing at the Mayall of less than 1" (NOAO Newsletter, March 2000). Similar concentrated effort at WIYN has quadrupled the likelihood of obtaining 0.6" or better ( NOAO Newsletter, March 2000).
At the Mayall, in addition to the usual computer and mechanical maintenance, installation of the servo system for the active f/8 secondary marks a critical milestone for the project. The active f/8, which will correct for coma induced by flexure of the telescope structure, will be commissioned during the fall and is expected to be in routine operation by the end of 2000B. Installation and commissioning of a wavefront camera, which will enable nightly wavefront measurements and ease construction of active optics lookup tables, is planned for 2001A.