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Proceedings Paper

A new Cassegrain calibration lamp unit for the Blanco Telescope
Author(s): S. D. Points; D. J. James; R. Tighe; A. Montané; N. David; M. Martínez
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Paper Abstract

The f/8 RC-Cassegrain Focus of the Blanco Telescope at Cerro Tololo Inter-American Observatory, hosts two new instruments: COSMOS, a multi-object spectrograph in the visible wavelength range (350 – 1030nm), and ARCoIRIS, a NIR cross-dispersed spectrograph featuring 6 spectral orders spanning 0.8 – 2.45μm. Here we describe a calibration lamp unit designed to deliver the required illumination at the telescope focal plane for both instruments. These requirements are: (1) an f/8 beam of light covering a spot of 92mm diameter (or 10 arcmin) for a wavelength range of 0.35μm through 2.5μm and (2) no saturation of flat-field calibrations for the minimal exposure times permitted by each instrument, and (3) few saturated spectral lines when using the wavelength calibration lamps for the instruments. To meet these requirements this unit contains an adjustable quartz halogen lamp for flat-field calibrations, and one hollow cathode lamp and four penray lamps for wavelength calibrations. The wavelength calibration lamps are selected to provide optimal spectral coverage for the instrument mounted and can be used individually or in sets. The device designed is based on an 8-inch diameter integrating sphere, the output of which is optimized to match the f/8 calibration input delivery system which is a refractive system based on fused-silica lenses. We describe the optical design, the opto-mechanical design, the electronic control and give results of the performance of the system.

Paper Details

Date Published: 9 August 2016
PDF: 9 pages
Proc. SPIE 9908, Ground-based and Airborne Instrumentation for Astronomy VI, 99082N (9 August 2016); doi: 10.1117/12.2232995
Show Author Affiliations
S. D. Points, Cerro Tololo Inter-American Observatory (Chile)
D. J. James, Cerro Tololo Inter-American Observatory (Chile)
R. Tighe, Cerro Tololo Inter-American Observatory (Chile)
A. Montané, Cerro Tololo Inter-American Observatory (Chile)
N. David, Cerro Tololo Inter-American Observatory (Chile)
M. Martínez, Cerro Tololo Inter-American Observatory (Chile)

Published in SPIE Proceedings Vol. 9908:
Ground-based and Airborne Instrumentation for Astronomy VI
Christopher J. Evans; Luc Simard; Hideki Takami, Editor(s)

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