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Hi everybody!I have a problem using ccdproc: although I assigned the overscan region of my images as biassec in the ccdproc parameters, the routine always uses the mean of the complete image to be substracted from the image. It shows as output:[quote:6b029ef58e]oct170071f.fits: Oct 16 15:24 Overscan section is [1028:1047,1:1024] with mean=9330.576
oct170071f.fits: Oct 16 15:24 Zero level correction image is masterbias[/quote:6b029ef58e]But using imstat, I get something around 300 as mean level of the overscan region. This means, it does know where the overscan region is located, but it ignores this. What am I doing wrong? with best regards,
MichaelPS: These are the ccdproc parameters:
[quote:6b029ef58e] images = "" List of CCD images to correct
(output = "") List of output CCD images
(ccdtype = "object") CCD image type to correct
(max_cache = 0) Maximum image caching memory (in Mbytes)
(noproc = no) List processing steps only?\n
(fixpix = no) Fix bad CCD lines and columns?
(overscan = yes) Apply overscan strip correction?
(trim = no) Trim the image?
(zerocor = yes) Apply zero level correction?
(darkcor = no) Apply dark count correction?
(flatcor = yes) Apply flat field correction?
(illumcor = no) Apply illumination correction?
(fringecor = no) Apply fringe correction?
(readcor = no) Convert zero level image to readout correction?
(scancor = no) Convert flat field image to scan correction?\n
(readaxis = "line") Read out axis (column|line)
(fixfile = "") File describing the bad lines and columns
(biassec = "[1028:1047,1:1024]") Overscan strip image section
(trimsec = "image") Trim data section
(zero = "masterbias.fits") Zero level calibration image
(dark = "") Dark count calibration image
(flat = "masterflat_*.fits") Flat field images
(illum = "") Illumination correction images
(fringe = "") Fringe correction images
(minreplace = 1.) Minimum flat field value
(scantype = "shortscan") Scan type (shortscan|longscan)
(nscan = 1) Number of short scan lines\n
(interactive = no) Fit overscan interactively?
(function = "chebyshev") Fitting function
(order = 1) Number of polynomial terms or spline pieces
(sample = "*") Sample points to fit
(naverage = 1) Number of sample points to combine
(niterate = 1) Number of rejection iterations
(low_reject = 3.) Low sigma rejection factor
(high_reject = 3.) High sigma rejection factor
(grow = 0.) Rejection growing radius
(mode = "ql")
[/quote:6b029ef58e]

Hello,From the information you show I can't see anything wrong and it is mysterious that the log output does show clearly that it knows the overscan section but gets a large mean value. The only way I could help would be to get a copy of the image file. If you want to do that you can put it on an ftp/http server at your end or use anonymous ftp to iraf.noao.edu/pub. Let me know (valdes@noao.edu) if you do this so I know to get the image and look at it.Yours,
Frank Valdes