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Proceedings Paper

Focas-Faint Object Classification And Analysis System
Author(s): J. F. Jarvis; J. A. Tyson
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Paper Abstract

A system for detecting and classifying images on astronomical plates is described. In particular, the very faint and barely resolved images of 24th magnitude galaxies are shown to be detectable and distinguishable from stellar images of similar brightness. The algorithms and other implementation con-siderations used in the construction of FOCAS are given. Detection and classification at 24th magnitude is achieved with N2 presensitized IIIaJ plates exposed for one hour in the KPNO 4-m telescope prime focus camera. For a digital 6000x6000 pixel image made from the central square area 37' on a side approximately 16000 objects are found to 24.7 mag on such plates. Since the resulting catalog of objects is 3 or 4 magnitudes deeper than existing surveys a variety of internal tests must be used to assess the accuracy and completeness of the list of objects. The tests and simulations made to support these claims are also discussed.

Paper Details

Date Published: 3 May 1979
PDF: 7 pages
Proc. SPIE 0172, Instrumentation in Astronomy III, (3 May 1979); doi: 10.1117/12.957112
Show Author Affiliations
J. F. Jarvis, Bell Laboratories (United States)
J. A. Tyson, Bell Laboratories (United States)


Published in SPIE Proceedings Vol. 0172:
Instrumentation in Astronomy III
David L. Crawford, Editor(s)

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