Complimenting OSC with Mono L and Ha

[AndyUK]

Sadly I haven't migrated away from DSS (yet), and I have neither AA5 or full PI (only the LE version, which I used to use for DBE). I do have Maxim though (although I've yet to try using it for callibration / stacking), but I don't know if it will perform automatic scaling ().

I just had a quick look at PI star alignment though, and it does look as though it might be able to do that...

Triangle similarity is invariant to translation, rotation, uniform scaling, and mirroring.

As you already have PI, it's certainly worth giving it a go...!

[For anyone interested, the full information on PI Star alignment is here, but halfway down it then drops into gobbledigook as to how it works... I stopped there ]

[ollypenrice]

I very much doubt that there's anything to be gained from doing a single stack from both cameras. Combining the separate stacks has always worked well for me. I remember Dennis (Roundycat) posting some helpful research saying much the same thing, though that's from memory.

Registar really is a dream for this kind of messing about, though.

Olly

[AndyUK]

Registar really is a dream for this kind of messing about, though

Plus 1 for Registar - It's SO easy to use...!

[ianaiken]

Olly - I assume that nothing would be gained if you had for each camera already attained, for instance, 100 subs? Let's say you were only able to get around 20 from each camera, then surely for increasing SNR more subs is better?

Registar sounds good though from what I've read on the website, but what I am finding is that PI can do everything, it just knowing where and how.

I'll have a look and see if I can find what Dennis wrote in the past about this, more of interest than anything else. For my case, I will be combining Ha with RGB in post for the next season so not so important but it's really interesting.

[ollypenrice]

I think that if you had a dozen subs from each camera then it would matter little whether you did a stack of 24 or a stack of 2 stacks of 12. I say 12 as a minimum per stack so that the Sigma routine has a chance to drive out rogue pixels from satellites etc.

You might also find that each separate stack of 12 had its strong and weak points so you might try combining them in Ps Layers and erasing the bad bits of one before applying it to the other. I've done this, for example, when in a desparate attempt to get some signal for the Praying Ghost, I shot some binned data which gave me nasty stars. I erased the binned stars when applying the binned image to the unbinned. It seemed a useful idea.

Olly

[ianaiken]

Thanks for that Olly, some good consideration points, I like the idea of getting the best of both.

Have you ever (or anyone else for that matter) imaged with two cameras on the same mount? I am wondering how to tackle the problem of dithering when there are two cameras, possibly taking different length exposures. I've been thinking about it for a short while now. While I can easily see how to control two cameras (three if you include guider) not sure how to go about dithering. I think this might be something which isn't possible (notes to ensure OBS is made big enough for two mounts).

Ideas?