Paper
7 March 2003 The L band high speed guide camera with nanomesh resonant dichroic
Author Affiliations +
Abstract
TEXES, the Texas Echelon Cross Echelle Spectrograph, is an ideal instrument to study molecular clouds at a spectral resolving power of 100,000 between 5 and 25 μm. In many molecular clouds, high extinction often means that no visible stars are available for off-axis guiding. At a resolving power of 100,000, only the very brightest sources can be observed while guiding on the power in the dispersed IR spectra. We present the design of a high-speed on-axis guider for TEXES operating at 3.65 μm, a wavelength outside the spectrometer operating band where many of the target sources are still detectable for imaging. We use a new technology gold nanomesh resonant IR filter/mirror from EDTEK, that transmits 3.65 μm light to the guide detector with a peak transmittance of 60% while reflecting light from 5 μm long-ward with 98% efficiency to the dispersing elements in the spectrograph. A PC controls clocking patterns for the CRC-463 detector from Raytheon Infrared Operations and the analog to digital conversion of signals with a 14 bit A/D card. Image centroiding is done in software and then offsets are sent to the telescope for pointing adjustments or tip-tilt corrections when a tip-tilt secondary is available. This system is a prototype designed to test the feasibility of a similar guider for EXES, the Echelon Cross Echelle Spectrograph, mounted on SOFIA, the Stratospheric Observatory for Infrared Astronomy.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Thomas K. Greathouse, John H. Lacy, Paul M. Harvey, Daniel T. Jaffe, Adrian H. Lu, and Mark D. Morgan "The L band high speed guide camera with nanomesh resonant dichroic", Proc. SPIE 4841, Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, (7 March 2003); https://doi.org/10.1117/12.459963
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KEYWORDS
Cameras

Optical filters

Telescopes

Sensors

Electronics

Transmittance

Spectrographs

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