Filter choice for newbie??

[Jbunky86]

Hi everyone
I'm new to the hobby and I'm looking at getting a filter for viewing and imaging.

My backyard is heavily light polluted and wondering any suggestions.
I mostly enjoy viewing/imaging galaxies and nebulars.

I would really like to cut out as much light pollution as possible.
Btw I image using a Dslr thru a c8 and ed80 triplet.

Cheers jason

[mental4astro]

Hi Jason,

There is a very good site that gives the rundown on filters:

Lumicon filters (http://www.lumicon.com/astronomy-accessories.php?cid=1&cn=Filters)

But in a nutshell here are some pointers on visual filters:

In a light polluted enviroment, an OIII (Oxygen III) filter is your best friend. However, these are only really good for nebulae. Galaxies glow across the entire spectrum of light, so an OIII filter won't help you here. What an OIII will do in a dark site with a galaxy is help show those nebulous areas within the galaxy. The catch here though is that these regions are really on visible in relatively close (large in the scope) galaxies. A big aperture is another big help too.

A TRUE UHC (Ultra High Contrast) filter is very good at a dark site to increase contrast with nebulae. What these will also do is help reveal particularly dark nebulae, like the Horsehead. UHC filters are also nebula filters, so no good for galaxies.

I only have an OIII filter in my kit. While an UHC filter has its place, I am quite happy with what an OIII gives me. Particularly from my home in Sydney.

Colour filters are very good with helping reveal particular features on the planets. One note of caution, I suggest you look very carefully at the colour filter selection chart from the Lumicon site, and then only choose two, three and no more than four colours for visual. Unless you are a hard-core planetary observer, you really won't get very much use out of these.

BUT, before laying your money down, I strongly suggest you try to get to a star party and see these various filters in action. This will really help make sense of a lot of the jargon and applications of these bits of gear. You can do a lot of money on these for very little return.

I'll leave the filter selection with imaging for other more qualified members. I can offer nothing in that field.

Mental.

[casstony]

Hi Jason, for visual use I think you'd be disappointed with the minor improvement UHC/OIII filters will give using a C8 in a light polluted yard. You either need to take the C8 to a dark site or buy a larger scope for your yard to make the filters worthwhile buying for visual use. (imho).

[mental4astro]

Hi Tony,

Good you should say that. It was only with an OIII filter that I was able to seen the dark pillars in Eta Carina from home in my C8. You do need to be patient though, as they are faint, and require averted vision to make them out. Mixing up the eyepieces being used will give different results with the filters too, and you'll find the best EP/filter/scope combination for any given object.

Sure, not as good a view as from a dark site, but if home is where you get to do most of your observing, I'd take what I can get, knowing, understanding and accepting the limitations.

[casstony]

It probably depends a lot on just how much light pollution is coming into the yard. I have two streetlights not far from my backyard and I observe from the shadow of a shed. Jason says his yard is heavily light polluted so I'm guessing it's at least as bad as my spot. I guess it also depends on one's expectations for the degree of improvement from the filters.

With my C11/filters I can see wisps of nebulosity extending well away from eta c and the brighter parts look very bright - looks a lot like a photo - I never found it exciting in the Meade 8" from my yard.

[Jbunky86]

Hi thanks guys,
Tony your backyard sounds exactly like mine it's just I'm getting some shielding from my fence. I find that latley I'm just to busy to drive to my fav dark site and more often I'm just whipping my gear out in the backyard.

I was reading about filters and hoping these could help with my sessions in the backyard.

Cheers
Jason

[casstony]

With your current scopes you might have more luck focusing your filtering efforts on imaging Jason, since you can use filters which cut out most/all light pollution but that are sensitive to light emitted by nebulae (eg. H-alpha filter).

I'm not into imaging but here's some info to start with:
http://starizona.com/acb/ccd/advequipfilters.aspx

http://starizona.com/acb/ccd/advimnarrow.aspx