Your Favourite Nebula Filter

StarGazing (Alex) · #1 05-11-2009, 08:34 AM

Hi all I am currently looking to purchase my first nebula filter and was wondering what experience fellow IIS members have had with them and what would you recomend.
Thanks Alex.

multiweb (Marc) · #2 05-11-2009, 08:37 AM

Quote:

Originally Posted by StarGazing

Hi all I am currently looking to purchase my first nebula filter and was wondering what experience fellow IIS members have had with them and what would you recomend.
Thanks Alex.

I have a 2" baader UHC-S which enhances contrast in nebulae. I used it a couple of times to image Eta, M16, M8 and it does a good job. I'm not sure visually as I'm not much of a visual observer.

jjjnettie (Jeanette) · #3 05-11-2009, 08:42 AM

I had the Baadar UHC filter and really enjoyed the views through it. I sold it on thinking that the O111 would be even better. Wish I hadn't now.

JethroB76 (Jeff) · #4 05-11-2009, 09:12 AM

DGM NPB filter - unfortunately need to be imported as no one carries them here

erick (Eric) · #5 05-11-2009, 09:29 AM

My experience to date is that they do different things on different objects under different sky conditions (light pollution mainly).

My current set (all 2") is:

DGM Optics NPB filter
DGM Optics OIII filter
Baader UHC-S filter

The DGM filters are sold by Omega Astrofilters. There is good detail on each filter on their site, including spectral transmission curves:-

http://www.omegafiltersebuyer.com/servlet/StoreFront

I recommend that you look for filter reviews by David Knisely. I think you'll find them on the Cloudy Nights forum.

Edit:- Here are some of his reviews:-
http://www.prairieastronomyclub.org/filters.htm
http://pages.sbcglobal.net/raycash/filters.htm
http://www.cloudynights.com/byauthor.php?author_id=2 (look on page 2 for reviews of the DGM Optics filters)

I love my NPB filter. It is magic on the Carina nebula.

I have used another brand of OIII filter for successfully increasing the contrast on planetary nebula, very useful when they are small and hard to distinguish from the starfield. Hopefuly the DGM OIII will do the same job.

I have looked at NGC 253 in light polluted skies using the UHC-S filter and thought - that's not much better than without the filter?

So I have plenty of testing to do. When I have a filter slide, I will mount all three and will be able to quickly swap between them for some rigorous testing.

cookie8 (Vincent) · #6 05-11-2009, 09:15 PM

I have a DGM NPB filter for 12" Dob visual in my suburban backyard.
Increase contrast for emission & planetary nebulae ....Lagoon,eta,dumbbell....all jump out at you. Very happy with it.

norm · #7 05-11-2009, 09:44 PM

NPB Filters are great all rounders:

Can be purchased on Ebay:

http://shop.ebay.com.au/?_from=R40&_...All-Categories

Cheers, Norm

erick (Eric) · #8 06-11-2009, 10:10 AM

Quote:

Originally Posted by norm

NPB Filters are great all rounders:

Can be purchased on Ebay:

http://shop.ebay.com.au/?_from=R40&_...All-Categories

Cheers, Norm

Recommended! Jim will look after you.

kustard (Simon) · #9 06-11-2009, 05:39 PM

oooh, those DGM Optics NPB filters look pretty nice

StarGazing (Alex) · #10 06-11-2009, 11:02 PM

Quote:

Originally Posted by erick

Recommended! Jim will look after you.

Looks like the DGM NPB filter is a winner, I have read so much about it. Erick you give the ebay seller the thumbs up ...... have you purchased through him, if so how was the transaction ?.
Cheers Alex.

erick (Eric) · #11 07-11-2009, 11:23 AM

Quote:

Originally Posted by StarGazing

Looks like the DGM NPB filter is a winner, I have read so much about it. Erick you give the ebay seller the thumbs up ...... have you purchased through him, if so how was the transaction ?.
Cheers Alex.

See:- http://www.iceinspace.com.au/forum/s...ad.php?t=48554

Jim Waters at the Ebay store told me later he should have sent what was his highest value order to Australia to date, via a registered post. He normally relies on regular US Postal Service.

Don Pensack · #12 07-11-2009, 11:24 AM

What differentiates one nebula filter brand from another is bandwidth. The narrower the bandwidth, the better the contrast--to a point. If the bandwidth is so narrow one of the intended wavelengths is partially blocked, then the filter is less effective.

If you buy only one filter, it would be a UHC-type, which passes the O-III and H-Beta lines in the spectrum. Some nebulae have a lot of emission at one or the other, and would be better-enhanced by a filter that just transmits that wavelength (example H-Beta only), but a good general use filter for nebulae is the UHC-type (UHC was a name coined by Lumicon, and it stuck).

Broadband, or LPR filters, are jus too wide to really enhance nebulae much, though they do seem to turn up the contrast a bit if you are already in dark skies. I wouldn't use one anywhere near a metropolitan area, though, as they don't block enough light.

Something to look for:
--transmission of over 90% at the correct wavelengths (486nm for H-Beta, 496nm and 501nm for O-III and all 3 for a UHC)
--near square-wave response curves
--no reports of bad threads that don't fit eyepieces
--very little response outside the correct wavelengths--preferably zero outside of the chosen wavelengths from 450nm to 700nm.

The spectrophotometer at work confirms a reported analysis of the DGM NPB. It is slightly narrower than the Lumicon in bandwidth.
So we have some choices from narrow bandwidth to wide (remember, narrower produces better contrast):

DGM NPB(the narrowest of the UHCs)
Lumicon UHC (a little wider)
Thousand Oaks Type 2
Orion Ultrablock
Astronomik UHC (one of the widest UHC filters)
Baader UHC-S (a narrow broadband, if you will)
Lumicon Deep Sky (a broadband filter)

I think TeleVue and Baader UHC filters have too-wide bandwidths (the TeleVue O-III filter is wider than the Lumicon UHC, for example), though they may provide pleasing images in small scopes if you know in advance that they will not provide the best contrast.

Hope that gives you an insight into how filters enhance nebulae. Since stars are full-spectrum objects, their lights are dimmed by good filters, but the nebulae aren't. You're turning up the contrast quite a bit, and that enables the really faint parts to stand out.

Blackant (Ant) · #13 07-11-2009, 11:46 AM

I just bought my first nebula filter for my 8" Dob last week on a trip to Melbourne, an Astronomics UHC-E filter.

I tried it for the first time on the Eta Carina nebula and Orion nebula's on Thursday night, wow

Even though I was only using a cheap GSO/Bintel 15mm wide view eyepiece and both nebula's were fairly low in the sky with hazy clouds about the filter made a HUGE difference.

I tried it both with and without the filter, and the subtle detail I could pick up was hugely improved with the filter, almost giving the nebula a 3 dimensional shape. I compared what I could see of eta carina with photo's afterwards, and although I obviusly couldn't see colour I could see a much bigger extent of it, subtle mottling and hugely improved contrast between the dark rifts and nebulosity.

The orion nebula was low down and covered with hazy cloud to the point that I could only just make it out with the naked eye but through the filter I could a huge extent of its "wings" with a subtle green colour.

Overall I'm really happy with it and am looking forwards to a hopefully clear dark night tonight.

Kind regards

Ant

GrahamL · #14 08-11-2009, 06:13 PM

I had a 1.25"lumicon uhc , and now a 2 " orion ultrablock , like Dons
post above suggests I thought the lumicon had a slight improvement in contrast.I'm not sure who stocks orion in aus these days
( couldn't find one here at the time ) I bought mine through one of those summer sale deals OS .. abought $100 or so from memory.

wavelandscott (Scott) · #15 09-11-2009, 03:26 AM

I'd recommend the DGM NPB as a good choice....

slippo74 (Cristiano) · #16 10-11-2009, 07:26 PM

Hi Alex,

I have an Astronomik UHC 2" and I'm extremely happy with that.
Although I'm sure you can get something similar on a more reasonable price.

troypiggo (Troy) · #17 10-11-2009, 07:30 PM

Looked at the Omega Filters website for the DGM NBP but they're out of stock. Anywhere else you can get them? I sent an email to them but no response yet.

mithrandir (Andrew) · #18 10-11-2009, 09:31 PM

Quote:

Originally Posted by troypiggo

Looked at the Omega Filters website for the DGM NBP but they're out of stock. Anywhere else you can get them? I sent an email to them but no response yet.

erick, we didn't pick up their entire stock did we?

erick (Eric) · #19 10-11-2009, 11:39 PM

Quote:

Originally Posted by mithrandir

erick, we didn't pick up their entire stock did we?

Craig.a.c (Craig) · #20 10-11-2009, 11:59 PM

I have a DGM Optics NPB Nebula filter (bought from a member on here). Have enjoyed many views through it. First time I looked at Eta and Orion through this filter just blew me away.