nebula filter?

lateralus · #1 14-12-2005, 08:36 PM

I'm looking at purchasing a nebula filter for my scope. I have a 12" f/5 dobsonian, and I'm rarely able to get out to dark sky sites

.
So! What would be a sensible choice considering these circumstances?

Also, what would the contrast be like with the filter you suggest for my scope?

Thanks!

P.S. I'm not exactly rich, so something in a sensible price range what be good!

Starkler (Geoff) · #2 14-12-2005, 09:06 PM

There is much written about filters. There are different types with varying degrees of effectiveness on different objects.

Have a read of this, it pretty much says it all.

http://www.prairieastronomyclub.org/filters.htm

jezza · #3 14-12-2005, 09:24 PM

Thanks for the link to info on Nebula filters. Very enlightening. I had a related question. Cheers

janoskiss (Steve H) · #4 15-12-2005, 01:35 AM

Best value is the DGM narrow band-pass filter. Darkens everything except the gases in nebulae. I found it excellent in light polluted Melbourne. E.g. Swan neb. Can hardly see it without filter, but stands out clearly and shows a lot more structure through the filter. I found the filter to be of limited use under dark skies.

janoskiss (Steve H) · #5 15-12-2005, 01:44 AM

You will find a comparative review (one person's opinion) of 26 different nebula filters in the August issue of Astronomy:

Phil Harrington, Astronomy, Aug 2005, vol. 33(8), pages 82-85.

If you can't locate a copy and want to have a read, PM me.

janoskiss (Steve H) · #6 15-12-2005, 01:59 AM

One more post and that's it. Promise.
dhumpie has a Lumicon UHC for sale at a bargain price. These are supposed to be excellent too.

iceman (Mike) · #7 15-12-2005, 06:17 AM

I can concur with the DGM Optics Nebula Filter - a very good price for a very good filter. About $100 cheaper than a new Astronomik/Lumicon OIII/UHC filter.

Are you after a nebula (narrowband) filter, or a skyglow (broadband) filter?

Starkler (Geoff) · #8 15-12-2005, 07:49 AM

Quote:

Originally Posted by janoskiss

. I found the filter to be of limited use under dark skies.

I have a Lumicon UHC and it works well in dark skies also

In light poluted skies I have to drape a cloth over my head to shield ambient light to get the full benefit.

iceman (Mike) · #9 15-12-2005, 07:54 AM

I agree with Geoff, I find the nebula (narrowband) filters to work equally as well under dark skies.

Striker (Tony) · #10 15-12-2005, 09:17 AM

Dont forget the Baeder UHC-s filter.

I used it on My Orion images....and will be taking it to lostock to see how it goes under darker skies.

I have both the 1.25" and 2" version..I probably want need my 1.25" anymore if your interested.

If your intested in the 1.25" $90 includes postage.

it's virtualy Brand new.

janoskiss (Steve H) · #11 15-12-2005, 09:17 AM

I didn't mean they don't work. I meant they usually don't show you more than the unfiltered view. Under dark skies I only use it on fainter objects occasionally to show me if I'm looking at a nebula or an unresolved star field.

ving (David) · #12 15-12-2005, 09:54 AM

ditto steve...wel i only have a broadband, but i still only use it on the faint ones

your light pollution must be shocking tho, i find the swan is quite bright (as long as theres no moon of course )

janoskiss (Steve H) · #13 15-12-2005, 10:24 AM

Quote:

Originally Posted by ving

ditto steve...wel i only have a broadband, but i still only use it on the faint ones

your light pollution must be shocking tho, i find the swan is quite bright (as long as theres no moon of course )

Yes, it's not too bad with no Moon. But it really stands out with the NPB filter Moon or not. Funny thing is though that I just don't bother deep sky observing from the back yard all that much any more. It seems a futile exercise when I consider how much more I can see at a locations even only 45 minutes' drive away.

Dobman (Simon) · #14 13-01-2006, 01:07 AM

Where can you get the DGM NPB filter from in OZ and who stocks the Orion filters?

iceman (Mike) · #15 13-01-2006, 05:53 AM

Hi Simon.

You can't get the DGM optics NPB filter in Oz - you have to order it from overseas. The 1.25" version was shipped to my door for AU$80 - a bargain when compared to the very similar in performance Lumicon and Astronomik UHC/OIII filters for AU$190.

Just go to the DGM Optics site and order online. They were on sale when I got mine, i'm not sure how much they are now but it'll still be significantly cheaper than the more expensive brand.

Dobman (Simon) · #16 13-01-2006, 09:19 PM

Thanks Mike, I've already sent an email. Hopefully it hasn't gone up much

Dobman (Simon) · #17 16-01-2006, 06:50 PM

Sent off email to DGM & got reply back within 24 hours (on a weekend too!) Dan @ DGM sent me a link direct to the filter ordering page. us$89 incl post (AU$115) Said it will be shipped within 24 hours. Great service & friendly too. He wished me good viewing
I ordered this filter on the strength of 2 reviews- one in Astronomy mag & one on cloudy nites. At this price it seems like a great deal compared to the cost of most filters thru Oz dealers. Has anyone used this filter?

janoskiss (Steve H) · #18 16-01-2006, 07:10 PM

Yes, I got mine from DGM too, no probs (1.25" version). It works very well, and it is quite impressive to see nebula appear from the murky skies, but once I got over the initial excitement, I haven't really used it very much. It is best for cutting out light pollution around nebulae, but I don't bother to observe much deep sky from the back yard. I rather drive to dark skies, where I usually prefer the views without the filter. I do use it for one purpose though, under dark skies: to distinguish between nebulosity and unresolved star fields, usually around the LMC.

iceman (Mike) · #19 16-01-2006, 07:37 PM

In my opinion, it's much more than a light pollution filter - in fact I wouldn't call it that at all.

While it's true that it will most likely help to view nebula from light polluted sites, at dark skies it's equally as useful as the view WITH the nebula is considerably different than WITHOUT the nebula. They're different views - I think it's worth seeing a given nebula in both ways, as to my eye, they show different detail.

The view of the tarantula NGC2070 or NGC366 (I think?) are just superb when viewed with this filter - a much different view than without the filter. And this view was at a reasonably dark site, in both my 10" scope and hector (20" scope).

janoskiss (Steve H) · #20 16-01-2006, 09:33 PM

Yes, I imagine the filter would be more impressive in a larger scope. It does darken the sky and stars a lot and the nebula only a little, so it's a targeted contrast booster and can bring out detail you would not see without it. Even though I rarely use it, I don't think I'll ever sell it because it works so well. I'm looking forward to trying it out in my 16+" Dob one day. :dream: