DSOs filters

[icytailmark]

I cant decide which filter to get. Im tossing up between Oxygen 3, and Ultra High Contrast . I mostly observe from my backyard which has tons of light pollution.



Skywatcher 12" Dobsonian.

[astroron]

Go for the UHC as it is a better overall filter for general observing, but not for galaxies.
O111 are usually used more for Planetary Nebula and some defuse Nebulae

[JethroB76]

yes, if you're only after one filter, get the UHC. The DGM NPB are very good performers at a good price, however can only be bought direct from the US

[wavelandscott]

Sound advice...

If you are going to get only one filer a UHC is the ticket.

I too recommend that DGM NPB (Narrow Pass Band)...

[Don Pensack]

Objects with full (wide) spectra are not helped by nebula filters. Only nebulae are helped a lot by this type of filter.
There are a few choices for visual observing:
UHC filter (transmits the H-Beta and O-III lines in the nebular spectra)
H-Beta filter (transmits only the H-B line)
O-III filter (transmits only the O-III lines)
The best contrast will be with the narrowest filter that lets through the light you want to examine. Filters with wider bandwidths pass more light of the stars, but have less contrast on the nebulae.

As a general rule, O-III filters seem to work best on planetary nebulae, while the UHC filters seem to work best on bright emission nebulae. The H-Beta filter enhances a small number of objects in the sky the best (e.g.Horsehead, California nebula, etc).
The problem with generalities is that there are usually exceptions, and that is the case here, too.
But if I were to recommend the order to get them it would be UHC first, O-III second, and H-Beta last.

Broadband filters notch out a few of the artificial light sources, but have little effect on diminishing light pollution. I think their best use is in an already dark sky just to tune up the contrast a tiny bit.

Unfortunately, there is really only one effective light pollution filter--gasoline. You put it in your car and drive your scope to darker skies.

[astro744]

Note the UHC narrowband filter typically includes the O-III and H-Beta emission lines and is an excellent all purpose filter but transmission and spectrum can vary between makes.

The O-III and H-Beta complement the UHC and for objects such as the Horsehead nebula, you need the H-Beta to see it more easily since contrast is further enhanced. However I would not recommend the H-Beta as your first filter since it blocks the O-III part of the spectrum.

Go the UHC first, O-III second and H-Beta third if you want.

[glenc]

My Lumicon UHC filter gets lots of use, and I sometimes use my Lumicon O-III. I usually start every observing session by looking at all the bright emission nebulae and large planetary nebulae that are above the horizon with a 21mm Orion Stratus EP and a UHC filter.

[icytailmark]

http://www.omegafiltersebuyer.com/servlet/the-2/astronomy-filters%2C-Galaxy-Contrast/Detail

so i should get this filter?

[wavelandscott]

The DGM NPB is a fine filter...I have it and like it.

If you have not yet read the filter article by David Knisely (spelling?) posted on Cloudy Nights I would encourage you to. He did a comprehensive assesement and the DGM fared well...

Are you thinking that you want the 2 inch filter or the 1.25 inch filter? (Which eyepieces do you want to use it with?)

[icytailmark]

im thinking bout getting the 2" 21mm ethos when it comes out because all my other eyepieces are 1.25's. I will use the UHC filter and 21mm ethos to view most DSO's i hope that will be good enough.