Which what filters

[Brycepj (Peter)]

Hi Everyone,
Last night had a good session on a nice clear night spent lots of time looking at Orion Nebula which was amazing. My question is from other images I have seen a filter has been used to bring out the detail red seems common.
I don't own any filters and being a newbie not sure what to buy or how to use them effectively.Do I need to buy the celestron box of filters .? Is one better than another? What do people use and how and why
Thanks

[Allan]

Hey Peter, I assume you want the filters for visual use. Imaging is a separate case. I would suggest steering clear of the filter sets, and rather buy better quality filters to begin with. Good filters like good eyepieces will last forever and can be used in all types of telescopes.

Narrow band filters make the Orion Neb stand out quite brilliantly, but be aware they do dim star fields, but that is just a function of what they are designed to do. That is isolate certain wavelengths of light to enhance the nebula. Red is a harder colour to detect at night because the human eye is not so sensitive to it, but a highly recommended filter is the DGM NPB which does pass some light at the red end of the spectrum. Another top filter is the Lumicon UHC and I would recommend either of these to start you off with in the narrow band/UHC class. The Astronomik UHC is good, but a bit "wider" than the other two, meaning it won't show quite as much contrast, but the star fields will be brighter.

After that you might consider an OIII filter, which is even more narrow in bandpass than the UHC types so will show extreme contrast on many nebula.

I have a collection of Broadband, Narrowband, OIII and H-Beta filters. Having these options covers pretty much everything in the sky. But the best advice is to start with a good Narrowband/UHC filter because it is the best all round filter to use on the biggest range of targets.

[glend (Glen)]

I would second Allan's advice re the DGM NPB for most nebula work. Some will say the OIII is best for the Horsehead but its pretty hard to see with most scopes from a metropolitan area. Good filters are not cheap, start with one.

[barx1963 (Malcolm)]

I am currently using Astronomik UHC and OIII filters and am very happy with them. For deep sky visual work a good UHC and OII really are the only ones you will need IMHO. You can get more exotic one (H-beta for example) but they have limited uses.
There are more broadband light pollution filters around, but I have never found them as useful, but in a bad light pollution area they may be worthwhile.
Avoid the filter sets, unless you are doing a lot of planetary work, really not much help.

Malcolm