Combining RGB images

Colin Clackson

I'm starting out with a monochrome camera and I'm trying to understand the workflow to be undertaken to achieve a master file for of images from each filter. When I load the images and calibration files into WBPP The result is one large monochrome file rather that three separate files according to filter. I thought the solution would be to run a WBPP script separate for each filter set and then combine those but the stars are not aligned. It seems to me that calibrating, aligning and integrating monochrome images is pretty standard fair so I'm thinking I'm missing something obvious. Can you offer any pointers?

Colin Clackson

Does WBPP group images by filter in post calibration? I didn't set the filter type in APT when I captured the images so the FITS header doesn't contain this information. If WBPP relies on this information to group images in post-calibration is there a way to force the grouping?

BlockHead

First... please do review FastTrack Training if you get a chance! 

Yes, WBPP does group images by Filter. And yes, the FITs header is used. 

If the information is not in the header... then how do YOU know which filter it is?? 

I assume it is because you put the information in the filename. Going forward you need to configure your acquisition software to put all of this information in the header. It needs to save the image type (dark, bias, light), the filter, the binning, pixel size... etc.

If you do not have this information in your files, the easiest way to solve this for the current data is to use the custom button in WBPP. You would select all of your Red data and fill in the information... most importantly that the filter for the group of files is "Red."

You need to do the same thing for your flats as well if the information is not there. Otherwise the files will not be matched. 

You can take care of this and run WBPP and process everything in one go.

-the Blockhead

Colin Clackson

Thanks for your reply, Adam.

I have completed the Fast Training, although admittedly many months ago, and many others of your excellent instruction videos. I’ve been using an OSC until now.

You are right. I’ve been tracking the filter type in the filename and file structure but have now configured the capture software to track this data in the FITS header.

I actually didn’t have any difficulty associating the darks, flats, and dark flats with the correct light frames, it was just that the process only generated one master light frame combining all three filters. The solution you offer is the missing piece, at least for this data set. Going forward I will be more mindful of the filter setting in the capture software.

Thanks very much for your quick response.

Colin