Two‐dimensional Analytical Modeling of Distortion and Sky Background in Multifiber Spectrographs: The Case of the Norris Spectrograph at Palomar Mountain
- 1 February 2003
- journal article
- Published by IOP Publishing in Publications of the Astronomical Society of the Pacific
- Vol. 115 (804) , 243-254
- https://doi.org/10.1086/345918
Abstract
A method for optimal reduction of data taken with multi-fiber spectrographs is described, based on global correction of their geometrical distortion. Though it was specifically developed for reducing observations performed at Palomar Mountain using the Norris fiber spectrograph, this method can be adapted to other types of multi-object spectrographs such as the multi-slit ones. Combined with a 2D analytical interpolation of sky-background that accounts for non-uniform spectral resolution, the Norris software package achieves very high accuracy in airglow subtraction, even in the near infrared (7000-9000A) where molecular band-emissions commonly induce strong artefacts that preclude clean sky subtraction whenever standard image processing techniques are used. Correlatively, an improvement by a factor of 2 on the precision of radial velocities is achievable. Throughout the paper possible improvements to the method are suggested for those devising similar packages for other instruments.Comment: 12 pages LateX, 4 PS figures, accepted for PASP (February 2003Keywords
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