processing nifs dark frames

Lorrie wrote on Sep 04, 2009

I'm having some difficulties getting my dark frames to cooperate in my calibration reduction steps. In any step when NSCUT is called, it requires an MDF attached to the file to know how to proceed. Darks don't get MDFs attached in the first few steps, and supposedly the later tasks NSREDUCE and NSFLAT know how to deal with darks lacking the MDF. However, when I try to follow the steps in the example reduction and process the darks in NSREDUCE, I just get an error from NSCUT telling me there's no MDF... when of course there's not. The exact error is:

FAIL: dark[MDF] - Extension not readable or absent
ERROR - NSCUT: Missing MDF data

I'm not sure what information you need in order to help, but just let me know and I'll post it. I'm running Iraf 2.14, gemini 1.10, and fedora 11.

Thanks!

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Lorrie wrote on Sep 04, 2009

Also, when I try to force the MDF to be attached in the NFPREPARE step, it says it does so in the output, but in fact does not (checked with gemextn). Thanks for all your help, I really feel like I've tried everything.

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monikval wrote on Sep 04, 2009

Hi Lorrie,
Since I had the same difficulties at the beginning, probably you have the same problem I had: Identify the difference between Dark frames and Flats-Off. Seems that the Flats-off can be use "as darks" in some sense and they don't generate the errors with the mdf that you're getting. Check your Flat-images to find which ones are Flats-On (=Flats) and which are Flats-Off (=Darks).
all the best,
Monik

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Last post on Sep 04, 2009