Is Batch Preprocessing able to match flat frames to lights using PA?

[PHannah]

I have looked for an answer to this in the forums but cannot find one. If the answer is there I apologize.

Where I have east & west images from a GEM mount (and rotator) and East and West flats,  is BPP clever enough to make east and west flat masters by filter, and then use the correct ones to calibrate the light frames? i.e. does it use the position angle from the FITS headers to do this?

Thanks
Peter.

[aworonow]

The short answer is 'Yes it can'
The way to do it is to use the "Add Custom" button and assign a name for a set of Lights and use the same name for the Flats you want to use

Alex

[PHannah]

Hi Alex thanks for the quick reply.

I take it you mean assign the same filter name, say RedEast, to the lights and flats taken on the same side of the meridian, and say RedWest to those taken rotated 180 degrees?
So in fact BPP does not match using POSANG, but if we pre-sort the lights and flats we can fool it into thinking they are taken through different filters, which it does match.

Peter

[aworonow]

Peter, Basically, you're right. If I wanted to add some data taken on October 1-5, through a Red filter, on the East, I would select the lights that match that set of parameters, fill in the filter dialog in BPP with something like Oct1_5RE, and use the same for the selected, matching Flats.

Alex

[astrovienna]

Thanks for this idea.  I'm in the same situation and never thought of that.

Kevin