1. Phasing the mirror segments of the Keck telescopes II: the narrow-band phasing algorithm
- Author
-
Jerry Nelson, Terry Mast, Gary Chanan, Mitchell Troy, Scott Michaels, Frank Dekens, and David Kirkman
- Subjects
Physics ,Wavefront ,business.industry ,Materials Science (miscellaneous) ,Fast Fourier transform ,Phaser ,Industrial and Manufacturing Engineering ,Deformable mirror ,Primary mirror ,Cophasing ,Optics ,Broadband ,Business and International Management ,Adaptive optics ,business ,Algorithm - Abstract
In a previous paper, we described a successful technique, the broadband algorithm, for phasing the primary mirror segments of the Keck telescopes to an accuracy of 30 nm. Here we describe a complementary narrow-band algorithm. Although it has a limited dynamic range, it is much faster than the broadband algorithm and can achieve an unprecedented phasing accuracy of approximately 6 nm. Cross checks between these two independent techniques validate both methods to a high degree of confidence. Both algorithms converge to the edge-minimizing configuration of the segmented primary mirror, which is not the same as the overall wave-front-error-minimizing configuration, but we demonstrate that this distinction disappears as the segment aberrations are reduced to zero.
- Published
- 2000
- Full Text
- View/download PDF