How Essential Are Filters?

[GH1967]

Are they more for specialised viewing (example lunar) or for the odd very bright object like Venus?

Would they be necessary for dob owners given they usually go for DSO's?

In broad terms, can someone summarise the types of filters and in what situations you use them?

Thanks

[erick]

Do a little searching of the threads -there is plenty of discussion and reference to articles etc. eg:-

http://www.iceinspace.com.au/forum/showthread.php?t=2109

http://www.iceinspace.com.au/forum/showthread.php?t=27821

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

http://www.iceinspace.com.au/forum/showthread.php?t=29302

Cheers
Eric