problem with o3 data

[Micke187]

I have collected some O3 data on the heartnebula but i think i got a gradient that dont think is part of the nebula.
I come and think if it could be straylight that has entered the tub or is it something else?
The HA data is clean from any gradients.
here is a image from 23 subs stacked and stretched.

[yobbo89]

i'ts hard to say , it does look a little abnormal,it still looks like you have some workable data, a background extraction in processing should help.

it looks like sky glow ie not from a direct local source and the vignetting is giving it a central structure . are you using an 8.5 nm oiii ? it pays to spend more on the oiii filter for a tighter bandwidth filter.

[Micke187]

Well i have Streetlamp about 30m away that glows bright so i thought it might be the culprit. But i dont get the light straight in the tube. If it could be that the light bounce of the dewsheild into the lens? But then again shouldnt the baffels stop that?
Yes im using the 8.5nm filter.

[Micke187]

But if i need to change filter maybe the new baader series would be good? The o3 is 4.5nm. Havent heard so much about them but its baader so it should be good quality. And alot cheaper then astrodon.

[yobbo89]

yes i wonder how a tighter cheaper oiii filter will perform over a slightly wider more expensive filter.

[Micke187]

Well as you might have seen in the heart nebula image i posted it was definitely workable data but it was some work to remove the gradients tho.
I have ordered some vantablack 3.0 paint to paint inside the dewshield to see if it could get better. If it wont get any better i will buy a narrower filter.

[mbenjaminz28]

Remember the Oiii emission line at 500.7nm is much more affected by light pollution than Ha data at 656nm so that's why your Ha data looks much better. Baader Oiii filters at 8.5nm are really much too broad for use in heavy light pollution, either by moonlight or street lamps. I had a Astrodon 3nm Oiii and could use it up until the moon was full, it worked that well.

[Micke187]

So i have had some major improvents on my o3 data and it looks like the black paint really made a difference. So my conclusion is that i was getting reflections from the streetlamps inside the dewsheild that bounce into the tube and thats why i got these gradients.

Here is before i painted with the black 3.0

And here is after i painted

So you see there is a really big difference.