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Mono capture process

Equipment RGB Monochrome
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Dunk avatar
Dunk avatar
Hi all,

about to get my first mono camera and was wondering if anyone can give me any advice/experience on a process when capturing multiple filters?

(I'm using an ASIAir Pro/EFW here, so everything is automated. Not concerned about effort, more about recommendations for best image)

Say I want to take 12 frames each RGB - what's the recommended approach:

12xR, 12xG, 12xB
or
RGB,RGB… 12 times
or
RRR,GGG,BBB,RRR,GGG,BBB…  4 times
or something else?

Or… does it make no real difference and I'm just fussing over nothing?

Cheers,

d.
Engaging
Kapil K. avatar
Kapil K. avatar
Hi D,
it doesn’t really matter in principle as long as your filters are parfocal. Otherwise, you might have to focus between each filter change. So in that case, doing ‘n’ Reds one night (or whatever time span you’d want), then re-focus and do ‘n’ greens next night .. and so on would be a better strategy. In general also, avoiding unnecessary Filter Wheel rotation would just be less error prone, IMO.

I personally do them in sets. For example, on a single night, I would do {25 x L, 15 x R, 15 x G, 15 x B}. That way, even after a single night of captures, I have a full set to process and play around with and course correct as needed. Once I get enough LRGB, I just go all in on Lum and/or H-alpha and get as many of them as I can on next set of clear nights. I try and post-process from time to time and call it done when I think I am getting to point of diminishing returns (usually happens around 15-20hrs of total exposure).

Hope this helps,

-Thanks,
K.
Helpful
urban.astronomer avatar
urban.astronomer avatar
Another aspect is how much variation and stability you have in the sky conditions. Where I live, clear nights are not that frequent, so if the seeing conditions are excellent one night, I prefer to rotate the filter wheel, RGB, RGB, .. in case I don't get the opportunity to gather more data in the near future. This way, you also ensure that you have roughly the same data quality from all the filters.

Before I started this procedure, it happened to me more than once that the clouds came in for long periods, and I had to wait for weeks to finish off a data set, missing data from only a single filter. And when the sky went clear again, the deep sky object had moved out of reach.

Think of it as not putting all the eggs in one basket (translated: Don't put all the data on one filter) ;-)

Cheers!
-Martin
Well Written Helpful Insightful Respectful Engaging Supportive
Dunk avatar
Dunk avatar
thx guys. some good advice!

Cheers,

Dunk.