How to create a multi-channel mosaic by Mabula

Data used in this tutorial is courtesy of Steve Milne

Data details:

4-panel multi-channel RGB mosaic of the Sadr region in the constellation of Cygnus.

The mosaic has a 2×2  panels (x3 -> 3 monochrome channels R,G,B) compostition with 10-15% overlap between the panels. So that’s 12 panels which we need to register as one multi-channel mosaic.

monochrome Atik 383L, William Optics Star 71 apo

Steve already created the 4 panels for each channel (R,G,B) in APP.

The goals are

  • to register the 12 panels in such a way, that the R,G and B mosaics are immediately perfectly registered with each other.
  • and that the 3 mosaics have the same image dimensions.

So that implies that both

  • the sky coordinates and
  • the field of view

of the 3 mosaics are exactly the same, so we can directly combine them into a RGB composite.

Gallery of the 3 indivdual mosaics, the green mosaic without LNC + MBB and the RGB composite created with only defaults settings in the RGB combine tool.

No attempt was made to correct the result for light pollution/gradients. That will be the topic of a following tutorial.

note 1:
This is R,G,B data, but this tutorial would equally apply to creating a multi-channel mosaic from different narrowband filter data (like SII, H-alpha, OIII) or for a multi-channel mosaic using monochrome H-alpha data with RGB data from a one-shot color camera.

note 2:
If you are creating a mosaic, first make the mosaic panels, and then register the panels as a mosaic. That’s the most efficient, fastest and most robust way. In one of the previous video tutorials, it was mentioned that you can load in all frames of all panels and create the mosaic. That is still possible, but it will take much more time and is less robust. Especially if you have lots of frames and lots of panel. So it’s recommended to first create the panels using regular integration.