1201.2336 (Steve B. Howell)
Steve B. Howell
Fringing in CCD images is troublesome from the aspect of photometric quality
and image flatness in the final reduced product. Additionally, defringing
during calibration requires the inefficient use of time during the night to
collect and produce a "supersky" fringe frame. The fringe pattern observed in a
CCD image for a given near-IR filter is dominated by small thickness variations
across the detector with a second order effect caused by the wavelength extent
of the emission lines within the bandpass which produce the interference
pattern. We show that essentially any set of emission lines which generally
match the wavelength coverage of the night sky emission lines within a bandpass
will produce an identical fringe pattern. We present an easy, inexpensive, and
efficient method which uses a neon lamp as a flat field source and produces
high S/N fringe frames to use for defringing an image during the calibration
process.
View original:
http://arxiv.org/abs/1201.2336
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