Must-Have filters?

[Lowepro]

I was wondering if there are filters that are must-haves?

I have nice dark skies and 12" dob and only do visual observing.

I know I definitely need a moon filter, as it is way too bright to look at.

What types of filters are worth investing in? And are the pricier ones worth it for visual observing?

I like to look at pretty much everything: planets, nebulae, etc.

Thanks :)

[erick]

There are no "must have", but...

Better than a Moon filter is two polarising filters - adjust the degree of crossing to get the darkening you want. Trick - put one polarising filter on the eyepiece, put the other on the bottom of an adapter, extension tube etc. Then just rotate the eyepiece to reach the darkening you are hapy with. But some say don't use a filter for Moon viewing:-

http://www.iceinspace.com.au/forum/showthread.php?t=28725

You just have to then live with a bright purple spot in front of your eye for many mins.

Some reading on filters:-

http://www.iceinspace.com.au/forum/showthread.php?t=23881

http://www.myastroshop.com.au/guides/filters.asp

http://pages.sbcglobal.net/raycash/filters.htm


But, if you want to spend a few dollars, I recommend this one to look at some nebulae - particularly the Carina nebula:-

http://www.omegafiltersebuyer.com/servlet/the-NPB-Filters/Categories