Abstract

Aspheric mirrors utilized in optical systems have, by tradition, relatively slow focal ratios (f/2.6 to f/5.0). The 5.0-meter diameter Hale telescope primary mirror, for example, has a focal ratio of 3.3. Future ground based telescopes are being considered with aperture diameters in the range of 10 meters to 25 meters. In order to keep the telescope length and building within realistic sizes, primary mirror focal ratios ranging from f/1.0 to f/1.5 will be required. In a similar manner, packaging limitations for future space telescopes will force even faster primary mirrors (f/0.8 to f/2.3). The 2.4-meter diameter, f/2.3, Space Telescope primary mirror has a faster focal ratio than any current ground based telescope larger than 2.0 meters in diameter. Both fabrication (processing) and metrology (testing) are issues that must be addressed in the manufacture of these fast aspheric mirrors.

© 1980 Optical Society of America