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Proceedings Paper

A Data Reduction Package For Multiple Object Spectroscopy
Author(s): J. M. Hill; J. D. Eisenhamer; D. R. Silva
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Paper Abstract

Instrumental efforts in Multiple Aperture Fiber Optic Spectroscopy (MAFOS) at Steward Observatory have greatly increased the observing efficiency for spectroscopy of clustered objects. The Medusa aperture plate spectrograph and its successor the MX mobile fiber spectrometer allow simultaneous spectra of 30 or more objects to be recorded. To carry out an effective scientific program, this increase in data collection rate must be matched with similar speed increases in data reduction over conventional techniques. We have developed the Medusa Automatic Reduction System (MARS) to reduce intensified CCD spectra from Medusa and "barefoot" CCD spectra from MX. Data produced by these multiobject spectrometers is in the form of two-dimensional images containing 44 to 66 individual spectra. The philosophy of MARS is to make "hands off" reduction possible for large quantities of similar data, and to accomplish this task in time comparable to that required for observing. Both hardware and software improvements were required to extract one-dimensional spectra from two-dimensional data frames in an efficient manner. A VICOM image processing system is used for image display and inspection. Two-dimensional processing of the CCD frames and extraction to one-dimensional files is carried out on a DG MV/10000. Our ridge finding algorithm for automatic location of the spectra in the CCD frame is described. Simultaneous extraction of calibration frames allows an automatic wavelength calibration routine to determine dispersion curves. Line measurement and cross-correlation techniques are used to determine galaxy redshifts. Sky subtraction, flux calibration, and flat field techniques on multiple fiber systems are also discussed.

Paper Details

Date Published: 13 October 1986
PDF: 14 pages
Proc. SPIE 0627, Instrumentation in Astronomy VI, (13 October 1986); doi: 10.1117/12.968149
Show Author Affiliations
J. M. Hill, University of Arizona (United States)
J. D. Eisenhamer, University of Arizona (United States)
D. R. Silva, University of Michigan (United States)

Published in SPIE Proceedings Vol. 0627:
Instrumentation in Astronomy VI
David L. Crawford, Editor(s)

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