Broadband Imaging and Moonlight

LRGB Light Pollution
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Anderl avatar
Anderl avatar

Servus,

is there a definite answer to the question if and when moonlight broadband is

1. worth it and
2. if heavy moonlight broadband data could even degrade the whole stack?

i am imaging a galaxie right now and i have little interest in getting sho data on it. sadly the moon is very bright right now and the effect on single lrgb frames is easily seeable. that leaves me with the options of shooting something else, stop ap until the moon is less influential again or just go for lrgb anyway.
i don´t really care if signal acquisition takes longer under given moonlight but there is one thing that bothers me, could the moon luminance frames actually destroy the rest of my lum stack? e.g. making it impossible to show faint stuff like ifn that would be visible without the moonlight diluted frames?

cs
Anderl


John avatar
John avatar

dont imaging i nthe same area as the moon.

im now only do objects in the north, because the moon is in the south.

i only use a uv/ir filter, with good flats etc its ok. there is enough good broadband objects in the north, Cepheus has much, Cygnus also.

Here in the north the sun almost not go down anymore, so broadband is limited to hours or so.

Good idea is objects like M13.

Tobiasz avatar
Tobiasz avatar

Hi,

  1. Depends on the effort you have to invest to start imaging. Do you have a semi permanent setup that only has to be turned on to shoot? Then I would do it. If you’re mobile like me, it’s not worth it in my opinion.

  2. Depends on your stacking program and the measurement algorithms. I throw everthing I have into PI WeightedBatchPreProcessing and let Pixinsight decide with “PSF Signal Weight”. Worse nights have less weight and therefore less impact on the stack.

Regards

Helpful
Anderl avatar
Anderl avatar

Tobiasz · May 25, 2026 at 04:43 PM

Hi,

  1. Depends on the effort you have to invest to start imaging. Do you have a semi permanent setup that only has to be turned on to shoot? Then I would do it. If you’re mobile like me, it’s not worth it in my opinion.

  2. Depends on your stacking program and the measurement algorithms. I throw everthing I have into PI WeightedBatchPreProcessing and let Pixinsight decide with “PSF Signal Weight”. Worse nights have less weight and therefore less impact on the stack.

Regards

little effort necessary. my setup is somewhat semi permanent.

  1. still the question remains. would you maybe get a better result by not throwing all the frames in? i had an project containing only ha and oiii and a few oiii frames which included cirrus clouds have made it impossible to bring out any oiii at all.
    clouds are not moonlight though…

Tobiasz avatar
Tobiasz avatar

I mean you can test it with stacking all nights or excluding the moon nights and see for yourself.

AstroGadac avatar
AstroGadac avatar

If you image in low Bortle then not worth it, as in 1h of data in low moon you will probably get better SNR than an entire night with a full moon.

If you live in Bortle 8/9 then image away, as long as your target is not too close to the moon.

Well written Helpful Respectful Concise
Tony Gondola avatar
Tony Gondola avatar

You can consider Moonlight to be another form of light pollution as it has pretty much the same effect. Now ask yourself, would you drive to a remote location with worse light pollution than you have at home? Of course you wouldn’t. If you can see the effect in your images then it’s too much. Just don’t do it. Shoot narrowband, bright lucky imaging targets, the Moon itself, anything that’s not as effected. IMO, it’s just not worth it.

Well written Concise Engaging
Anderl avatar
Anderl avatar

Tony Gondola · May 25, 2026 at 05:37 PM

You can consider Moonlight to be another form of light pollution as it has pretty much the same effect. Now ask yourself, would you drive to a remote location with worse light pollution than you have at home? Of course you wouldn’t. If you can see the effect in your images then it’s too much. Just don’t do it. Shoot narrowband, bright lucky imaging targets, the Moon itself, anything that’s not as effected. IMO, it’s just not worth it.

Hey tony,

I can clearly see the difference between frames where cars drove by versus those without, as well as between images taken under a 20% moon and a completely dark sky. I’m confident I could even detect differences in frames captured while a funfair is running 10 km away compared to when it’s not.

Do you think adding 100h of quality lum data from bortle 7 skies to 1h of data of the same setup from bortle 1 would be a good thing? Neutral? Maybe even harmful if the goal is to bring out faint stuff?

Well written Respectful Engaging
bigCatAstro avatar
bigCatAstro avatar

It has never worked out for me due to the inevitably that Moonlight will expose all the flaws with my imaging train. Strange gradients and flats not calibrating correctly have been a couple of headaches I’ve experienced when shooting when the Moon is over 50% luminosity.

Concise Engaging
Tony Gondola avatar
Tony Gondola avatar

Anderl · May 25, 2026, 05:53 PM

Tony Gondola · May 25, 2026 at 05:37 PM

You can consider Moonlight to be another form of light pollution as it has pretty much the same effect. Now ask yourself, would you drive to a remote location with worse light pollution than you have at home? Of course you wouldn’t. If you can see the effect in your images then it’s too much. Just don’t do it. Shoot narrowband, bright lucky imaging targets, the Moon itself, anything that’s not as effected. IMO, it’s just not worth it.

Hey tony,

I can clearly see the difference between frames where cars drove by versus those without, as well as between images taken under a 20% moon and a completely dark sky. I’m confident I could even detect differences in frames captured while a funfair is running 10 km away compared to when it’s not.

Do you think adding 100h of quality lum data from bortle 7 skies to 1h of data of the same setup from bortle 1 would be a good thing? Neutral? Maybe even harmful if the goal is to bring out faint stuff?

What I know is that the better the data, the better the result. I would hope that you are culling bad frames as a matter of course. In the end, it’s up to you. I don’t shoot below 60 deg. elevation, even on dark nights. It’s just the way I like to work.

Well written Concise