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Optimal addition of images for detection and photometryIn this paper we describe weighting techniques used for the optimal coaddition of charge coupled devices (CCD) frames with differing characteristics. Optimal means maximum signal to noise (S/N) for stellar objects. We derive formulas for four applications: (1) object detection via matched filter, (2) object detection identical to DAOFIND, (3) aperture photometry, and (4) ALLSTAR profile-fitting photometry. We have included examples involving 21 frames for which either the sky brightness or image resolution varied by a factor of 3. The gains in S/N were modest for most of the examples, except for DAOFIND detection with varying image resolution which exhibited a substantial S/N increase. Even though the only consideration was maximizing S/N, the image resolution was seen to improve for most of the variable resolution examples. Also discussed are empirical fits for the weighting and the availability of the program, WEIGHT, used to generate the weighting for the individual frames. Finally, we include appendices describing the effects of clipping algorithms and a scheme for star/galaxy and cosmic-ray/star discrimination. scheme for star/galaxy and cosmic-ray/star discrimination.
Document ID
19950034216
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Fischer, Philippe
(AT&T Bell Laboratories, Murray Hill, NJ United States)
Kochanski, Greg P.
(AT&T Bell Laboratories, Murray Hill, NJ United States)
Date Acquired
August 16, 2013
Publication Date
February 1, 1994
Publication Information
Publication: Astronomical Journal
Volume: 107
Issue: 2
ISSN: 0004-6256
Subject Category
Astronomy
Accession Number
95A65815
Funding Number(s)
CONTRACT_GRANT: NAS5-26555
Distribution Limits
Public
Copyright
Other

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