need a sticky on filters

troypiggo (Troy) · #1 04-03-2009, 02:17 PM

As a newbie to this astro stuff, I'm finding it very confusing about all the different kind of filters. Not the RGB ones for imaging on monochrome cameras, but OIII, Ha, Hb, UHC and so on.

I understand that each of them filter different wavelengths of light and so bring out better detail in different objects depending on what light they're emitting or reflecting. I get that. But it would be handy to have a list of all the different types of filters, what wavelengths they block/allow, what they're best for (kinds of nebulae, light pollution etc), and whether they're best for visual, observing or both.

If there's already a thread like that here, feel free to point me in that direction, but I reckon it'd be a good sticky because that's the first place I look. The "show us your filters" sticky in this section doesn't really informative in that respect, unless the info is buried within the thread.

Whatchya reckon?

wavelandscott (Scott) · #2 04-03-2009, 02:23 PM

One of the best resources for information like you are asking about in my opinion is available on the Cloudy Nights website. Search their articles and you will find some comparisons from David K. (forgot his last name) he is from Nebraska (I think) in the US and as far as I am concerned is a filter "guru"...he has compared most of them out there and has outlined which work best visually on what targets.

troypiggo (Troy) · #3 04-03-2009, 02:41 PM

Found them.

David Knisely:
Useful filters for viewing deep-sky objects
Filter performance comparisons for some common nebulae

And some others:
Astronomical filter curves

troypiggo (Troy) · #4 04-03-2009, 05:29 PM

Just to clarify my understanding of those articles above because I am only interested in (SLR) photography at the moment - he mentions that broadband "light-pollution" (LPR) filters can be somewhat useful for photography of wide star fields where there's skyglow, but narrowband "nebula" filters like UHC and OIII are not recommended for photography. He does recommend if you're only going to get one filter, get the UHC, but I'm assuming that's only for visual/observing rather than photography?

So what filters are recommended for photography? At dark sites only? At light polluted sites?

wavelandscott (Scott) · #5 05-03-2009, 02:32 AM

Sorry, I can't help you on the Astro Photo front...I'm purely a visual observer...

It might be worth starting a thread (or searching) asking that specific question...maybe in the Astrophotography sections...