So how do I combine this?

Hi Sara,

So we have a multi-channel mosaic, probably similar to this one of Jeroen Moonen? :

https://www.astropixelprocessor.com/community/gallery/first-mosaic-and-preprocessing-in-app/#post-461

The best way to do this, is to

1) make the individual panels in Ha and OIII first.

2) then register all panels, so Ha & OIII simultaneously, as a mosaic.

3) then in the integration step, to make the mosaic of only Ha, only select the Ha panels. Similar to OIII. Then both Ha and OIII mosaics, should be registered to each other and should have the exact same image dimensions so you can load them directly into the RGB combine tool.

If this is unclear, I propose you send me the panels, and I will create a new video tutorial for this as well. We don't have a multi-channel mosaic video yet 😉

I guess this is also related to your RGB combination and same size requirements question?

Cheers,

Mabula

I have been doing this as far as I know ....

1- Stacking each OIII and Ha pane separately

2) Making a mosaic of the INDIVIDUAL panes 

3) Loading them in, star analyse and register

4) Saving each REGISTERED 2 pane

5) That's where it stops..... RGB will not combine them as they are not the same size.... This is really infuriating and such as shame that it's not working as I would expect it to. Theya re not the same size as the OIII in this case is VERY out of shape compared with the Ha.... but they ARE registered as the the stars are in the SAME position.

I just want them to combine.....  No drama, no fuss and no telling me that they are different sizes,...... I KNOW they are different and I don't care!! They are registered and that should be that.

Hi Sara,

It will be solved if in

2) you register all panels of Ha and OIII at the same time. If you don't do this, you will not have any guarantee that the mosaics can be combined with sub-pixel accuracy.

If you register the individual panels of the 2 mosaic separately, you will have different field of views for both mosaics and possibly even slightly different optical distortion corrections. 2 different registrations are always relative and that's the reason why the data should be registered as a whole. If you do, it should work perfectly 😉

This is really infuriating and such as shame that it's not working as I would expect it to. Theya re not the same size as the OIII in this case is VERY out of shape compared with the Ha.... but they ARE registered as the the stars are in the SAME position.

Maybe it's my way of looking at this and my thoughts on how to handle this properly that upsets you? Combining your data is really possibly and with sub pixel accuracy, but you need to register the whole multi-channel mosaic in one go. I can't see any other way around that. If you don't do that, then the H-alpha and OIII mosaic will have to be registered again to each other, which you want to prevent for an optimal result probably...

I just want them to combine.....  No drama, no fuss and no telling me that they are different sizes,...... I KNOW they are different and I don't care!! They are registered and that should be that.

So, no, I have thought long and hard about this but I simply can't agree with you on this issue.

The mosaics are registered, yes, but not with each other. If they were, than both mosaic should have the same field of view and coordinate system. With different sized mosaics, the field of views and coordinate systems will never match with subpixel precision without a re-registration ;-(

I will try to make a video soon, showing exactly how you can make a multi-channel mosaic.

Kind regards,

Mabula