Light Pollution and Mono Camera + filters

[Sabalias]

Hi All,

I've been doing a bit of imaging (getting to grips with the 1600mm and filters) and I have a question. I get quite a lot of sky glow (I'm assuming it's light pollution as the moon was not an issue at the time and there isn't any in the narrowband images) and I was wondering if I would be better using a light pollution filter at the end of my field flattener or processing out the gradient (which creates its own problems)? Obviously, narrowband imaging is a solution but not for all targets (I understand). I'm not very happy with the star shapes but that is a separate issue I am working on. First image is just cropped and a bit noisy, but you can see the gradient; the second is the full size image but the gradient has been removed in processing (which is leaving a kind of black speckling across the image). Images below are from only a couple of hours total subs (LRGB and narrowband) processed in DSS and then in Affinity Photo.

 

Many thanks,

Stu

[Lee_P]

I shoot from a city centre (but using an OSC camera rather than Mono). I haven't found any broadband light pollution filter to be helpful, and instead rely on long integration times. More info here. Other people find them useful though; I think it depends on your kit and local sky conditions. So, if you want to go down the light pollution filter route, I recommend trying to borrow a few and test them out to see if any work, and if so which is best for you.

[Sabalias]

Thanks Lee.  Fortunately I’m not in the middle of a town but I am kind of surrounded by them so your information is very useful. I do need to add more data (clouds permitting).

[Clarkey]

I live on the edge of town (Bortle 5/6) and I do not find LPF's useful. Particularly, if you have a lot of LED lights they don't work very well in my opinion. Personally, I try to collect as many photons as possible and remove any gradients in processing. If you have one particular type of light such as sodium or mercury vapour you might benefit from filters - but to be honest these are becoming quite rare these days.

I would suggest that a good astro specific gradient removal is worthwhile.  I mainly use APP for gradient removal (of if I have the time PI). Whilst Affinity is quite good the gradient removal is not as good, and you tend to get something that looks a little too 'flat'.