batch pre processing - how to ignore filter name?

[urbanMark]

I'm trying to recover from an oversight on my part - On a recent trip I took a bunch of Luminance frames but only R, G, and B flats. Since there are some dust motes and vignetting, I'd like to use the R (or what ever) flats for Luminance. Is there a way (short of editing the FITS header on every file) I can force the PI pre processing script to use say the R flats with the L frames? Any suggestions?

[RickS]

Build a master flat for the R filter and then use the BPP script "Add Custom" button to load it as a master flat for the L filter.

Cheers,
Rick.

[urbanMark]

Thanks Rick! That was easy. Unfortunately the red flat didn't do quite as good a job removing the dust mote from the luminance frame as I hoped, but still better than no flat.

[Geoff]

The dust motes on the R, G or B filters won't be the same as the dust motes on the L filter, so the best you can hope for is the removal of vignetting and not the removal of dust motes. In fact, using a flat that is not taken through the luminance filter will likely introduce artifacts by trying to remove dust motes (on your substitute filter) that are not present on your luminance filter. Have you tried the simple solution of using DBE on the luminance? It's pretty good for fixing vignetting.
Geoff

[urbanMark]

Hi Geoff,

Yes, I wound up using DBE to fix the issue. I had a rather stubborn dust mote on the L frame so I had to resort to lots of manually placed points in my DBE model, but eventually got a reasonable result. And FYI - I take great care to keep my system clean, but have to remove the camera to transport to a dark site, and I guess something got on the L filter in the process despite my extreme care and only being open for a minute. But shame on me for forgetting L frames in my flat sequence.