# Re: new UMAX-Patch available

William L. Sebok (wls@astro.umd.edu)
Tue, 26 May 1998 11:40:58 -0400 (EDT)

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Oliver.Rauch@Wolfsburg.DE says:

> It looks like a white calibration table for each pixel of the ccd that
> is used for the requested scan. So - I think - if a CCD-pixel has an other
> output level than the other CCD-pixels, it can be corrected that way.
> May be it is possible to do a kind of highlight-function by that.

This sort of correction has to be done very carefully when one uses a ccd
camera for Astronomical purposes. It's called a "flat-field" calibration and
was often done by taking pictures of the inside of the closed telescope dome.
In fact sometimes it was hard to see things until this correction was done.
I'm not surprised that a way of doing this has been provided in a scanner that
uses a ccd detector.

Bill Sebok Computer Software Manager, Univ. of Maryland, Astronomy
Internet: wls@astro.umd.edu URL: http://www.astro.umd.edu/~wls/

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