creating masks in IRAF

rohit wrote on Apr 03, 2008

I would like to create a mask using one of our spectrum of a template star. Basically instead of having fine lines, I would like to have square blocks, which make up the spectrum. How do I do that in iraf?

I also have a dat file of the spectrum in addition to fits file.

Thanks,

Rohit

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Mike Fitzpatrick wrote on Apr 03, 2008

I'm not quite sure I understand what you're after, is this a 1-D spectrum where you want to create a mask of specific features (or continuum), or a 2-D spectrum where you want to mask multiple orders/background?

There are a number of mask-making tools already in the system (do a "cl> refer mask" for a list) that could be used. Tasks like IMEXPR can also make a mask simply using an expression and by specifying the output with a .pl extension (see the help page) A task such as BLKREP can extend a 1-D mask into a 2-D mask by replicating columns; if you're starting with a 2-D image then a simple threshold using IMEXPR could be what you need. For more complicated masks you might look at MSKREGIONS, MSKEXPR, or TEXT2MASK.

Hope this helps, if you can be more specific about what you're doing I might have other suggestions.

Cheers,
-Mike

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Last post on Apr 03, 2008