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Paper: Concurrent Science and Wavecal COS Data
Volume: 347, Astronomical Data Analysis Software and Systems XIV
Page: 464
Authors: Hodge, P.E.
Abstract: Wavelength calibration for the Cosmic Origins Spectrograph (COS) is achieved by taking an exposure (a wavecal) of an internal emission-line lamp and comparing the observed location with the expected location. In order to correct for possible mechanism drifts during exposures which can be more than an hour long, a new observing mode has been proposed whereby the line lamp would be turned on briefly several times during a science exposure. This is practical because the science and wavecal spectra fall on different parts of the detector, and because COS data will normally be taken in time-tag mode, where the time and pixel coordinates are recorded for each detected photon. This paper describes the calibration of such data.
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