Applied Optics · 2000 · 220 citations · 11 references
Natural SciencesAstronomyPhysicsObservational AstronomyOptical AstronomyOpticsOptical AberrationsPhysical OpticsTelescope OpticsDynamic RangeMirror SegmentationTelescope AberrationsTelescopes
The broadband algorithm previously achieved 30 nm phasing accuracy for Keck’s primary mirror segments. This study introduces a complementary narrow‑band phasing algorithm. The narrow‑band algorithm, though limited in dynamic range, is faster than the broadband method and attains about 6 nm phasing precision. Cross‑checks confirm both algorithms, which converge to an edge‑minimizing configuration that aligns with the wave‑front‑error‑minimizing configuration when segment aberrations are eliminated, demonstrating high confidence in their performance.
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.
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Phasing the mirror segments of the Keck telescopes: the broadband phasing algorithm
G. A. Chanan, Mitchell Troy, Frank G. Dekens et al. · Applied Optics · 1998 · 234 citations
Natural Sciences, Astronomy, Physics +14