Omega Opitcal filters - experience anyone?

[mental4astro (Alexander)]

Hi all,

I've come across this mob from the USA who produce astronomical filters, such as OIII.

http://stores.ebay.com.au/BJOMEJAG-E...i.html?_fsub=2

They have been very careful not to use terms as 'UHC' or 'UHC-S' but very specific in the transmission description. This alone has impressed me as these terms have be misrepresented by some high profile companies from thier orthodox definitions.

What blows my socks off is the price of a 2" Hb & OIII filter for $US105!

They also sell very narrow band OIII filters for CCD imaging.

Maybe they are the manufacturer of the branded types?

Has anyone had experience with these?

Cheers,

Mental.

[JethroB76 (Jeff)]

These are actually the guys that make/sell the well known and loved DGM optics NPB UHC-style filters - I haven't bought through their ebay store but I think astronut has..

[ausastronomer (John Bambury)]

Hi Alex,

Jeff is correct. These filters were originally sold under the DGM Optics label and are now sold under the manufacturers label which is Omega. Dan McShane owns DGM optics.

These are very high quality filters. I have a DGM NPB filter in 1.25" and 2" format and it is an excellent filter in every respect. It is a very narrow pass UHC filter and is almost a hybrid UHC/OIII filter. It works extremely well on a wide variety of targets. I also have Astronomiks UHC, OIII and H-Beta and my DGM NPB is my most used filter.

Cheers,
John B

[mental4astro (Alexander)]

Well, I took a leap of faith and ordered an OIII/Hbeta 2" filter from Omega. Took two weeks to arrive, and tonight was the first chance I've had to give it a bit of a go from home. A dark sky review is still to come.

The package I recieved was surprising, and a little disappointing. A bubblewrap envelope containing inside a light cloth wrapper around the 2" filter. Nothing more than dumb luck prevented the worst from happening to the filter.

The metal ring contains no identifying markings. Only a print out of the transmission properties and a receipt of payment accompanied the filter. Real bargain-basement stuff.

The scope I used for my initial test was my 8" f/4 dob. The test eyepiece my 2" 30mm GSO Superview, giving 26.7X and a 2.5deg FOV. Just a short session to give the filter an bit of first light.

First target was Eta Carina. Holy heck! All 2.5 degrees were filled with bright and faint nebulosity! The bright section around the star Eta Carina revealed the 'keyhole' and much more detail. Surrounding lobes of nebulosity surrounded the brightest wedge, and then festoons of fainter nebulosity surrounded the entire complex. Stunning, even from my light polluted skies.

My second and last test target was M8 and M20. Both not only sit comfortably within the 2.5deg FOV, but the glow of both nebulae is quite extensive and noticeable. M8 had the appearance of a rose flower in full bloom, layered, textured and big. M20 is much smaller, with just a small soft glow that surrounds the core stars of the nebula. The famous Trifid shape is too small for this magnifiation to be seen, but the size and shape of the nebula is outstanding.

Though I'm disappointed at how the filter arrived, its performance is most impressive.

This first point of the delivery system is the big let down though. If it weren't so flimsy, I'd highly recommend these filters. Instead, I can only say 'worth considering', unless something at Omega Optical changes.

Cheers,

Mental.

[erick (Eric)]

Originally Posted by mental4astro

First target was Eta Carina. Holy heck! All 2.5 degrees were filled with bright and faint nebulosity! The bright section around the star Eta Carina revealed the 'keyhole' and much more detail. Surrounding lobes of nebulosity surrounded the brightest wedge, and then festoons of fainter nebulosity surrounded the entire complex. Stunning, even from my light polluted skies.

Mate! Wait until you buy their DGM filter and turn it on the Carina Nebula - it is even better than the OIII filter! Promise! Trust John B on this. And David Knisely (Cloudy Nights). See http://www.cloudynights.com/item.php?item_id=1578 You just HAVE to get one!

I bought just under $1,000 of filters from the Ebay store 12-18 months ago - a bulk order for about five IISers, including myself. I had plenty of message contact with them through the process. Apart from getting lost in transit for a few weeks (I suspect they were sitting in Customs while they waited to see if anything further arrived in my name pushing the total over the GST trigger), I was very happy, and, I believe, so were the other buyers. I don't recall any problem with packaging.

[mental4astro (Alexander)]

Thanks Eric.

I've just found the DGM filter ebay list. Most interesting the reviews, and the PRICES! Especially for 2" filters with known pedigree.

[erick (Eric)]

...and we bought at an exchange rate of 80c, thinking it couldn't get better!

[mental4astro (Alexander)]

What would be the smallest aperture suggested for the NPB filter?

[mercedes_sl1970]

Originally Posted by mental4astro

What would be the smallest aperture suggested for the NPB filter?

Interested to hear about this too.

Andrew

[erick (Eric)]

I was happy with it in my original 8" reflector.

[ausastronomer (John Bambury)]

Originally Posted by mental4astro

What would be the smallest aperture suggested for the NPB filter?

Hi Alex,

It would work well in a telescope of 4" aperture or more. Whilst the view would be dim in a small scope, the contrast gain would still be quite noticeable under dark skies. It's all about increasing the signal to noise ratio, which applies to all filters. I have used OIII filters which block out more light than the NPB in 4" and 5" scopes in the past, with good results. I have used the Astronomiks OIII on a 4" Takahashi FS-102 and a Televue Bandmate OIII on a Televue NP-127. In fact at 2007 Texas Star Party, myself, Gary Kopff and Andrew Murrell were observing with Al Nagler with his personal Televue NP-127 and we were looking at the Veil Nebula. We first tried a Televue Bandmate filter (OIII). We then tried a Televue Nebustar filter (UHC) and then Al Nagler decided "for fun" he would "stack" both filters. The view for a 5" telescope with both filters stacked was exceptionally good. Which shows the critical thing with all deep sky observing is dark skies.

In a medium/large scope the DGM NPB works very well on a few targets which "some" narrowband or OIII filters don't do all that much with. The Crab Nebula (M1) which is a supernova remnant, is one of these for instance. It also does a tremendous job on the Orion Nebula (M42), the Tarantula Nebula (NGC 2070), Eta Carina (NGC 3372) and a host of other planeteries and emission nebula. If I could only own 1 filter (I own > 30), the one filter I would pick each and every time would be the DGM NPB.

In regard to the packaging, my DGM NPB filter, which I purchased over 5 years ago, came direct from DGM optics, not Omega who are the manufacturer. My filter was very nicely packaged in a hard but slightly flexible plastic case and was clearly machine laser inscribed on the side as to its origin, size and type. Couldn't fault how it arrived.

Cheers,
John B

[astronut (John)]

I've used these filters for 4 years.....great value and they give excellent results!!

[bahoogas (James)]

Originally Posted by ausastronomer

My filter was very nicely packaged in a hard but slightly flexible plastic case and was clearly machine laser inscribed on the side as to its origin, size and type. Couldn't fault how it arrived.

I bought my DGM NPB from eBay two months ago from the seller you've linked above. It came just like this, with small plastic case and laser inscription, and arrived very quickly. I would recommend the seller as well as the filter.

[Acrab (Victor Martinez)]

DGM "NPB" filter, is considered the best world UHC type filter. I love him

[skies2clear]

Have to completely agree with the praise for the NPB filter.

[wavelandscott (Scott)]

Top shelf!

[mental4astro (Alexander)]

A little update.

I had my first dark sky use of this new OIII filter last new moon. Its first target was Eta Carina -

OMG!

I never imagined how far reaching this giant really is.

Fabulous filter!

[casstony]

Originally Posted by mental4astro

I never imagined how far reaching this giant really is.

Even in my light polluted backyard the eta c. nebula looks almost photographic with an DGM NPB filter; the brighter parts are more contrasty with an 1000 oaks OIII, though the NPB shows nebulosity extending further out and shows more fine detail within the nebula. (using C11 and 41 Panoptic).

I think it's very helpful to mention the scope, eyepiece and observing conditions used since they have such a big influence on the view through the filter.

[mental4astro (Alexander)]

Ok Tony, no problem:

17.5" dob, 30mm GSO Superview (1 whole degree AFOV), at Wiruna, Ilford, NSW, seeing 8/10, transperancy 4/5.

[casstony]

Have you had a chance to compare the OIII and NPB on eta c. Alexander? I'm wondering if the NPB would still show a more expansive/detailed nebula under dark sky as it does for me in light pollution, even though the Oaks OIII shows greater contrast in the brighter parts.