We present the design for a near-infrared (JHK) fringe tracker to be used at the CHARA Array, a long baseline optical interferometer located at Mount Wilson Observatory. The CHARA Michigan Phase-tracker (CHAMP) is being fabricated and tested at the University of Michigan and will be transported to the CHARA Array for general use. CHAMP is separate from the science combiners and can therefore be optimized for fringe tracking. It will modulate around fringe center by 1-2λ at up to 500 Hz and calculate phase offsets in real-time using a modified 'ABCD' method . Six pair-wise Mach-Zehnder combiners will phase the entire Array. We give an overview of the optical layout and discuss our design strategy. Components such as the path-length modulators, low-OH fiber transport system, 1024x1024 HAWAII-1 detector, and control computer are discussed.
|Title of host publication||Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series|
|Number of pages||1|
|Publication status||Published - 28 Jun 2006|
|Name||Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series|
Berger, D. H., Monnier, J. D., Millan-Gabet, R., ten Brummelaar, T. A., Muirhead, P., Pedretti, E., & Thureau, N. (2006). CHARA Michigan phase-tracker (CHAMP): design and fabrication. In Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (Vol. 6268, pp. 3). (Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series). https://doi.org/10.1117/12.672168