The 6.5 Meter Mmt'S F/5 Wide-Field Optics And Instruments

In 2003, the converted MMT's wide-field f/5 focus was commissioned. A 1.7-m diameter secondary and a large refractive corrector offer a 1degrees diameter field of view for spectroscopy and a 0.5degrees diameter field of view for imaging. Stellar images during excellent seeing are smaller than 0.5" FWHM across the spectroscopic field of view, and smaller than 0.4" across the imaging field of view. Three wide-field f/5 instruments are now in routine operation: Hectospec (an Rsimilar to1000 optical spectrograph fed by 300 robotically-positioned optical fibers), Hectochelle (an Rsimilar to40,000 optical spectrograph fed by the same fibers), and Megacam (a 340 megapixel, 36 CCD optical imager covering a 25' by 25' format).