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I have this problem, i'm processing some WFPC3 with xzap extern package but i'm doing it such a way the task is applied in layer [1] which contains 1 half of the detector and then another run with the [4] extension which contains the other half of the detector. The thing is that i have only one bad_pixel_mask.fit file with an extra column that indicated in which detector the bad pixel is.

Is it possible to separate the bad pixel mask into 2 files for processing with each layer? the xzap input image is an image which is originated by taking the [1] layer of the WFPC3, so it's a simple image, then i do the same and take the [4] layer but i bet xzap does not know that one of them is the CCD 1 or 2 of the WFPC3.

This is an output of the bpx file. I tried to edit it in a text editor but it complains to be a binary format with no ascii text.




Thanks in advance

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Lic. Santiago Roland - Los Molinos Observatory - IAU Code 844 - Licensed Radio Amateur CX1DR - Montevideo, Uruguay

Please help me...

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Lic. Santiago Roland - Los Molinos Observatory - IAU Code 844 - Licensed Radio Amateur CX1DR - Montevideo, Uruguay

I'm not sure I understand what you're doing, and I'm not at all familiar with XZAP, but ....

You can use a task like TSELECT to create separate mask tables based on e.g. 'ccdchip' column value, you then use the separate masks when processing the [1] and [4] extensions. To edit the table manually use the TEDIT task rather than vi/emacs.

You might also have a look at the CRUTIL package in NOAO.IMRED as an alternative way to remove cosmic rays.

Thanks a lot, is just i could not open the bad pixel mask with an ordinary text editor, so it has to be done by an internal IRAF task that understand the format of the file. I just want to make 2 bad pixel masks, one using the CCD#1 entry and one using the CCD#2 entry so i can apply any task (say, xzap) and there wont be any doubt what pixel mask the task is applying to the raw images.

Can i do that right? to edit the table and say, eliminate all the CCD#1 lines and keeo the CCD#1, and in another copy of the file, so the opposite so i would end up having 2 masks for separate chips, right?

Will keep looking.

Thanks man

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Lic. Santiago Roland - Los Molinos Observatory - IAU Code 844 - Licensed Radio Amateur CX1DR - Montevideo, Uruguay

Part of my confusion about your question is that you have a bad pixel mask in the form of a table, this is normally a pixel mask image (i.e. a file with a ".pl" extension). Additionally, I don't see where XZAP uses this mask directly, so I assume you're doing some other steps first.

Anyway, you can split the table based on the chip number using something like



When using the .pl form of a mask, you could do something like use the PROTO.MSKREGIONS task to create a mask from the table data (not directly mind you, I mean you could use the information to generate the regions descriptor expected by the task). In CRUTIL you could then use CRFIX to interpolate across the mask regions and the process the output image. This way, you could explicitly create the mask for each chip and process the [1] and [4] extensions separately.

Hope this helps.

Inside xzap.cl script there is this line at the beginning



What does it mean? in my script i call the xzap this way



@pdarks are single extension images of one half of the detector [1], the other half is in the extension [4] but i have this only badpixel mask that contains both detectors bad pixels.

I run this for [1] extension images (that are saved in other filenames as single extension pixel images) and then run for the [4] extension but xzap cannot know which detector is to apply the correct bad pixel values.

xzap run fine like this (i.e. no output errors) but this have to be wrong in some point, this way separating bad pixel masks is the only way i'm sure the correct mask is applied.

Anyway, i could not find much info on xzap task, except some papers that make comparisons of cosmic rays removal tools and algorithms, but i think omasks parameter is the masking file, otherwise i got it all wrong and i need to re-run everything, which in any case is not that bad.

btw, i'm trying to keep cosmic rays because we are trying to make some CR statistics along some years, so i'm removing CR in images and then removing the cosmic-ray-removed image from the original one so i end up with zero background images and cosmic rays that are above the background level, kind odd, but makes sense for processing with sextractor or matlab later.

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Lic. Santiago Roland - Los Molinos Observatory - IAU Code 844 - Licensed Radio Amateur CX1DR - Montevideo, Uruguay

The help page description of the parameter is:



It later goes on to say:



So in your mask file I think you will want the bad pixel regions to be marked as 0, then the CRs will be detected everywhere else (assuming the rest of the mask is all 1). But again the XZAP task isn't expecting a FITS table as a bad pixel mask, it's expecting an image (either regular FITS or a .pl file). You will still need to split the table/mask as I suggested before, and then call XZAP twice with different input lists for each chip and its corresponding mask.