A 4-meter McMath Telescope for the Infrared

Abstract

Having no window and a filled aperture, i.e., no occlusion by secondary optics, the all-reflective McMath telescope is a proven IR facility. Beyond about 2 μm, it is diffraction limited, however. Engineering studies show that the McMath building could accommodate an increase to a 4-m aperture with a 6-m alt-azimuth feed, permitting sub-arcsec resolution to 12 μm. The use of cooled, solid aluminum mirrors would eliminate “mirror seeing”, which plagues non-vacuum solar telescopes.