Batch Preprocessing script for RGB

[awachter]

If I have RGB data from different days and have processed the data for each channel using the batch preprocessing script, how do I combine the three color channels? Does the LRGB tool do automatic star alignment before combining the color channels or do I need to do a manually star alignment of the three channels before combining them with the LRGB tool?

[pfile]

somehow you need to get the frames registered to one another.

if you dump the R, G, B into BPP together, they will all be registered to the reference frame you choose.

if you did BPP 3 times with 3 different references, then you'll have to pick one of the masters as a reference and align the other two channels to that master.

the LRGB combination tool (or ChannelCombination, or PixelMath - all of which can be used to create an RGB image from 3 masters) will not align anything; they expect that the images will already be aligned.

rob

[awachter]

I can't dump all the L, R, G and B frames into BPP together since they all use different flats and darks (because of different exposure times). But I got the gist of the story: use the same frame as a reference for all the individual batch preprocessings. Thank you very much for your response!

[pfile]

yes you can, BPP sorts out the flats and darks for you!

rob

[awachter]

Brilliant! Thanks

Andreas

[pfile]

caveat: your fits headers have to be in order, or the filenames must have the filter names in them and the names have to match of course.

if you create the master flats outside of BPP it may not work; i assume the fits headers of the master flats generated by BPP must be modified to include the filter name by BPP itself.

it should key off the filenames if the fits headers are not right though.

the whole purpose of BPP was to simplify calibration and registration of the multitude of files generated when using mono CCDs and filter wheels...

rob