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Re: Odd issue with master bias and dark frames

Posted by karenacollins on Jun 01, 2021; 4:27am
URL: http://astroimagej.170.s1.nabble.com/Odd-issue-with-master-bias-and-dark-frames-tp1579p1580.html

Hi Mike,

I also see the problem you are seeing when attempting to open the mdark_1.497_2x2.fits file you provided using the latest AIJ daily build. However, if I rebuild the master from the 10 darks you provided the new master dark opens as expected. Can you let us know which version of AIJ you used to create the master dark (use => AIJ_Toolbar => Help => About AstroImageJ)? Also, if you are not using the latest "Daily Build", could you please update to the daily build using these instructions and let know if the problem persists.

Karen

On 5/31/2021 12:51 PM, Michael Collins [via AstroImageJ] wrote:
  While doing some engineering work over the weekend, I captured sets of bias and dark frames intended to calibrate my on-sky images. I've done this before using other cameras and capture software, so the process is reasonably familiar to me. Looking at my data afterward, I encountered no difficulty nor saw any error or warning messages when the master bias and dark frames were generated. I'm unable to use the masters to calibrate the image sets, however -- they are rejected with the message: "Unable to open FITS file <path/filename>: IO error: java.io.IOException: Invalid FITS header", followed by an "open failed" dialog. The first error is also reported if I attempt to open any of the master images using File -> Open... ds9 does not report any problems with any of the masters, and inspection of the header data using imhead shows no obvious problem, though I note that BITPIX is 16 in the original FITS headers and -32 in the masters.

  A set of darks and the corresponding master are available in <https://tmckepsj.org/files/Dark_1.497.tgz>. Not sure what I'm doing wrong, but I'd be interested in learning.

  -- Mike --
--
Michael Collins
Instrumentation Group
Lowell Observatory
Flagstaff, Arizona



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