Omega Galaxy Contrast Enhancement Filter

[Littleguy80]

Discovered this filter through a dealer ad on ABS this morning. It sounds interesting though I have to admin to bring skeptical as to it’s effectiveness. Has anyone tried one?

http://www.omegafilters.com/565rb-1790.html

[alanjgreen]

Its a light pollution filter so I would be somewhat sceptical. Comparing to the Astronomik then it blocks most (but not all) of the stated light pollution wavelengths except those below 500nm.

for visual, filters do NOT improve galaxies unless you are in light pollution which you want to remove in which case an Astronomik CLS (visual) filter would be the best bet.

The Astronomik transmission chart is here

https://www.firstlightoptics.com/astronomik-filters/astronomik-cls-filter.html

the Baader neodymium filter is another choice, the transmission chart is here

https://www.baader-planetarium.com/en/filters/baader-neodymium-(moon-and-skyglow)-filter.html

what you need for galaxies is DARK SKIES and the right eyepiece!

[Littleguy80]

Thanks Alan. The name is just marketing spin then! I’ve played with filters on galaxies from home and got minor improvements in contrast but not detail. I have a Neodymium filter which is really useful for the planets but I don’t tend to use it on anything else.

I normally save the faint objects for a dark site visit. As you say, no substitute for dark skies!

[alanjgreen]

There is mention of the "DGM Galaxy enhancement filter" in this cloudynights thread that is discussing filters for galaxies and night vision

https://www.cloudynights.com/topic/610939-viewing-galaxies-aperture-vs-night-vision/

The DGM did nothing on galaxies for the guy that bought it!

I am waiting for another guy (who has bought the Astronomik CLS Visual) to test it out (in the same thread)...

[Littleguy80]

15 minutes ago, alanjgreen said:

There is mention of the "DGM Galaxy enhancement filter" in this cloudynights thread that is discussing filters for galaxies and night vision

https://www.cloudynights.com/topic/610939-viewing-galaxies-aperture-vs-night-vision/

The DGM did nothing on galaxies for the guy that bought it!

I am waiting for another guy (who has bought the Astronomik CLS Visual) to test it out (in the same thread)...

Interesting thread. Doesn't sound like NV or the filter do much in terms of enhancing galaxies. I would think NV could be good for looking for large nebulae within the closer galaxies though. M33 would be a good target to test NV on.

[GavStar]

6 hours ago, Littleguy80 said:

Interesting thread. Doesn't sound like NV or the filter do much in terms of enhancing galaxies. I would think NV could be good for looking for large nebulae within the closer galaxies though. M33 would be a good target to test NV on.

Neil,

NV works very well on edge on galaxies like m82, the needle or Sombrero. It’s not good at the face on spiral ones at least partly due to the 685 filter which is needed to block out the LP (the 685 seems the best filter for galaxies and clusters).

I’ve had a lot of fun looking at galaxies with NV in my back garden in London this spring. Pre NV, galaxy viewing was pretty much a waste of time.

Gavin

[Littleguy80]

1 hour ago, GavStar said:

Neil,

NV works very well on edge on galaxies like m82, the needle or Sombrero. It’s not good at the face on spiral ones at least partly due to the 685 filter which is needed to block out the LP (the 685 seems the best filter for galaxies and clusters).

Ive has a lot of fun looking at galaxies with NV in my back garden in London this spring. Pre NV, galaxy viewing was pretty much a waste of time.

Gavin

Thanks Gavin. Interesting info. Now I think about it I recall seeing some of pictures of galaxies through the NV. If it wasn’t for the cost, I’d definitely give NV a go. Very neat tech! Would you see the same gains in the views from dark skies using NV that you do with a traditional eyepiece?

[GavStar]

18 minutes ago, Littleguy80 said:

Thanks Gavin. Interesting info. Now I think about it I recall seeing some of pictures of galaxies through the NV. If it wasn’t for the cost, I’d definitely give NV a go. Very neat tech! Would you see the same gains in the views from dark skies using NV that you do with a traditional eyepiece?

Good question. I haven’t really managed to get the NV out under dark skies yet - moon has been out or I’ve been clouded out. Very frustrating.

However, my understanding is that NV gives similar gains under dark skies so the views should be even better. Certainly that’s what the reports in the US say. I will report back at some point but it may be September now given that the nights are getting shorter quickly now.

But really I think the key benefit of NV is for those of us who live with LP skies and allowing us to see stuff (like galaxies) that we normally wouldn’t see.

[alanjgreen]

1 hour ago, GavStar said:

Neil,

NV works very well on edge on galaxies like m82, the needle or Sombrero. It’s not good at the face on spiral ones at least partly due to the 685 filter which is needed to block out the LP (the 685 seems the best filter for galaxies and clusters).

Gavin

Maybe the Astronomik CLS visual will out perform the 685?

The visual version is IR-pass whilst the CCD is IR-blocking so it's the visual version that we would need!

A couple of US guys have now bought the CLS so hopefully they will tell us. I am not convinced the 685 will do anything for me in Cumbria so I am watching the CLS closely...

[Timebandit]

 

 

 In my opinion rather than spending money on the light pollution filter.  You would be better off and get much better results spending the money on some petrol instead and travel to a Dark site.

Get to a Dark Site , and those Galaxy's will pop out to your eyes  ?

 

 

[Littleguy80]

2 minutes ago, Timebandit said:

 

 

 In my opinion rather than spending money on the light pollution filter.  You would be better off and get much better results spending the money on some petrol instead and travel to a Dark site.

Get to a Dark Site , and those Galaxy's will pop out to your eyes  ?

 

 

Totally agree. I didn’t realise it was a light pollution filter. I was fooled by the name!

[Stu]

48 minutes ago, GavStar said:

Good question. I haven’t really managed to get the NV out under dark skies yet

If I were a betting man (I’m not, too poor!) I would say that NV should perform very well on galaxies under a dark sky. If you think about it, the darker background of a good site is effectively what you are achieving by heavy filtering under light polluted conditions, then amplifying the improved contrast. Having decent contrast to start with means unfiltered, or less aggressively filtered galaxy views should amplify well with NV in dark conditions.

Probably haven’t explained that very well....

[Littleguy80]

5 minutes ago, Stu said:

If I were a betting man (I’m not, too poor!) I would say that NV should perform very well on galaxies under a dark sky. If you think about it, the darker background of a good site is effectively what you are achieving by heavy filtering under light polluted conditions, then amplifying the improved contrast. Having decent contrast to start with means unfiltered, or less aggressively filtered galaxy views should amplify well with NV in dark conditions.

Probably haven’t explained that very well....

Made sense to me. It was the mention of needing a light pollution filter for the NV that prompted the question

[GavStar]

12 minutes ago, Stu said:

If I were a betting man (I’m not, too poor!) I would say that NV should perform very well on galaxies under a dark sky. If you think about it, the darker background of a good site is effectively what you are achieving by heavy filtering under light polluted conditions, then amplifying the improved contrast. Having decent contrast to start with means unfiltered, or less aggressively filtered galaxy views should amplify well with NV in dark conditions.

Probably haven’t explained that very well....

Yes agreed Stu. I think under dark skies the USA folks use less aggressive filters such as the 640 or 610 or even no filter at all. Although PeterW has indicated that he found the 640 disappointing even under darker skies I think. 

An issue with NV is that it is not good in the blue spectrum (eg poor at reflection nebulae) and I think that also limits to some extent how good NV is with face on spiral galaxies.

[Stu]

3 minutes ago, GavStar said:

An issue with NV is that it is not good in the blue spectrum (eg poor at reflection nebulae) and I think that also limits to some extent how good NV is with face on spiral galaxies.

Don’t some of the galaxies like M101 or even M31 have Ha regions in them which might show up nicely with filtering?

[Don Pensack]

The best use of the DGM/Omega GCE filter is under already-quite-dark skies, when you need to simply turn up the contrast a tiny bit

without damaging the stars.  This filter differs from a piece of glass only in that the middle of the spectrum (where a lot of light pollution exits)

is about 50% filtered out.  Ergo, its action is very subtle, and most effective at producing a very subtle improvement in contrast.  The name is marketing hype.

However, be aware that, unlike nearly every nebula filter, this one can be used at any magnification you choose.