title: Interferometric hartmann wave-front sensing for active optics at the 6.5-m conversion of the multiple mirror telescope.
abstract: A little-used interferometric modification to the classical Hartmann optical test is being used for active optics corrections at the 6.5-m Multiple Mirror Telescope (MMT) Observatory. The technique produces compact interference spots whose positions depend on discrete wave-front phase-difference errors. A diffraction model illustrates the formation of interference spots. The limitations on wave-front sampling that are due to atmospheric seeing are estimated. Two data reduction matrix strategies are given. A single correction of collimation and primary mirror figure produces a nearly diffraction-limited telescope image. Wave-front polynomial coefficients ranging from several nanometers to several micrometers in amplitude are reliably detected.
authors.affiliation: Multiple Mirror Telescope Observatory, University of Arizona, Tucson 85721-0065, USA. swest@as.arizona.edu
authors.forename: Steven C
authors.initials: SC
authors.lastname: West