8 replies to this topic

[Zuben el Genubi]

Think I might have posted on wrong forum before … filters seems to be more an ‘eyepiece’ than ‘General’ question … so will ask a bit differently here.

 

Does anyone know the differences between the Orion SkyGlow and Astonomik UHC-E … they look similar to me from what I can see.
 
Are these almost the same? Are there any real differences?

 

thanks

[Zuben el Genubi]

I think I may have found an answer, if anyone else was interested …

the answer comes from a useful website Don elsewhere on the internet posted / Starman1 on cloudy nights 

 

https://searchlight....d-153d7e7c0eb8#

 

 

It seems they are very similar … but because there is some variation with testing of the Orion SkyGlow … sometimes it is narrower … sometimes a bit broader than the UHC-E (which in itself is obviously broader than the straight UHC narrowband filter from Astonomiks and others… although when I bought the UHC-E the advertising made me feel like it was a UHC for smaller apertures)

[Zuben el Genubi]

 

Interestingly the Baader Moon and SkyGlow is quite different form the Orion SkyGlow (even though the names do not make that difference  so obvious)

 

 

 

Edited by Zuben el Genubi, 29 June 2022 - 01:09 AM.

[Starman1]

The Orion Sky Glow filter is an average broadband filter, with a broad transmission bandwidth in the blue-to-green end of the spectrum, and a broad bandwidth in the red.

Before the advent of LED lighting, it could have been called a light pollution reduction filter.

The contrast enhancement is quite small.

 

The Astronomik UHC-E (E stands for economy) is similar to the economy UHC filters from China (though it is German), with a wide bandwidth in the blue-green

and the red.  If you had to pigeon-hole the filter, you'd call it a "narrow broadband".

Contrast enhancement would be just a hair better than the Sky Glow simply because of a slightly narrower bandwidth in the blue green.

You might consider this a better performing broadband.  Used as that, it's quite a decent filter.

 

As the filters continue to get narrower in the Blue-green, contrast enhancement picks up.

There are filters in this middle realm, between a broadband and a narrowband, like the DGM VHT, and a few others.

I never understood the why of these filters--not broad enough to be a broadband and not narrow enough to function well on most emission nebulae.

 

Better nebula viewing can be obtained from true narrowband filters, with blue-green bandwidths of 21-28nm, and as long as they pick up the H-ß and O-III lines in the spectrum

at a high % transmission, will yield great views of emission nebulae.

Examples:

Astronomik UHC Visual

TeleVue BandMate II Nebustar

Orion Ultrablock

DGM NPB

Lumicon Gen.3 UHC

Thousand Oaks LP-2

[Zuben el Genubi]

Thanks for the reply

 

is there any value / point to the Baader moon and sky glow, which appears to have a more unusual transmission pattern (? Some call it ‘notch’ filter I think)?
 

I’m interested theoretically and from your experience, Also any reason to add something like that to what I currently have (the Astronomik UHC and O-III (and as per your advice use the UHC-E as a narrow broadband filter) )?

[Starman1]

The Baader Moon & Sky Glow filter is an excellent Jupiter filter, as the Baader Contrast Booster filter is excellent on Saturn and Mars.
As Deep Sky filters, though, they are very mediocre. The UHC-E will do much better and the regular UHC even better than that.
Where the broader filters have a place is when you are already under dark skies and the nebulae only need a slight contrast boost and you don't want to kill all the stars in the field.

[Zuben el Genubi]

So the Baader moon and SkyGlow is different a enough from the Baader contrast filter to make both worth considering? From the spectrum analysis the contrast filter is similar but cuts out the blue end of the spectrum

 

i think I’m leaning towards these as an alternative to regular color filters

 

thanks again for your experienced insights

[pregulla]

The Astronomik UHC-E (E stands for economy) is similar to the economy UHC filters from China (though it is German), with a wide bandwidth in the blue-green

and the red.  If you had to pigeon-hole the filter, you'd call it a "narrow broadband".

Contrast enhancement would be just a hair better than the Sky Glow simply because of a slightly narrower bandwidth in the blue green.

You might consider this a better performing broadband.  Used as that, it's quite a decent filter.

From my experience comparing Optolong UHC, Optolong L-Enhance (27nm?), Svbony Sky Glow:

Sky Glow - hard to see a difference between filtered and unfiltered view under Bortle 6 skies, even harder under dark skies. But I like how it works on Jupiter.

Optolong UHC makes a decent improvement on nebulae. About 80% of that of L-Enhance under btighter skies or for low power faint objects. Under dark skies and 2mm exit pupil it's performance is pretty much equal to L-Enhance

[Starman1]

From my experience comparing Optolong UHC, Optolong L-Enhance (27nm?), Svbony Sky Glow:

Sky Glow - hard to see a difference between filtered and unfiltered view under Bortle 6 skies, even harder under dark skies. But I like how it works on Jupiter.

Optolong UHC makes a decent improvement on nebulae. About 80% of that of L-Enhance under brighter skies or for low power faint objects. Under dark skies and 2mm exit pupil it's performance is pretty much equal to L-Enhance

As nebula filters usage moves toward the 2.5mm exit pupil range, the effectiveness of the filters drops.

The reason is that the background is already dark, so background darkening has less effect, and the nebula itself is getting dimmer.

It is for this reason that 10x/inch of aperture (a 2.5mm exit pupil) is usually recommended as the highest power to use a nebula filter with.

 

However, there is not really a ceiling for the filters.  It depends on bandwidth.

A wider filter, like a broadband, can be used at a somewhat higher power (say, up to 12-13x/inch, or a 2mm exit pupil) without excessively dimming the field or nebula.

That would explain why you see little difference between the Optolong UHC (47-48nm bandwidth) and the L-Enhance (27nm bandwidth) at a 2mm exit pupil.  The L-Enhance would

provide more contrast but with the darker background, its superiority to the UHC would be significantly reduced by the higher power of a 2mm exit pupil.

At lower powers (4mm exit pupil, maybe), the L-Enhance should work much better.

 

What you could also use is a decent dual-wavelength (495.9nm and 500.7nm) O-III filter for use on planetaries, supernova remnants, and Wolf-Rayet excitation nebulae.

Your L-Enhance should be a fine narrowband filter for the large hydrogen gas clouds (e.g.M8, M20, M17, M16, M42).

Look for something in the 11-16nm bandwidth for optimum enhancement, like:

Lumicon O-III Gen.3
Intercon Spacetec (ICS) O-III (made by Astronomik)
Tele Vue Optics Bandmate II O-III (made by Astronomik)
Astronomik O-III Visual
DGM Optics O-III
Orion O-III

Edited by Starman1, 30 June 2022 - 09:10 AM.