Would UHC filter help

[Charlie 2436]

Hi All I had my new 6” achro refractor out for the first time the other night and everything looked as if it was misty, l mean I could see the planets it’s just that the background was like a slight mist rather than black. Is this down to light pollution ? ( I live in Glasgow ) and would the Astronomik UHC filter help or is it just for viewing nebula.

 Thanks Robert 

[NGC 1502]

2 hours ago, Charlie 2436 said:

Hi All I had my new 6” achro refractor out for the first time the other night and everything looked as if it was misty, l mean I could see the planets it’s just that the background was like a slight mist rather than black. Is this down to light pollution ? ( I live in Glasgow ) and would the Astronomik UHC filter help or is it just for viewing nebula.

 Thanks Robert 

Hi Robert.  UHC filters are designed for enhancing some deep sky objects but not all - definitely not good for galaxies and star clusters.  Planetary nebulae ( not planets ! ) are usually enhanced with a UHC.  The one and only time I’ve used a UHC on a planet is with my two small refractors to view Venus.  The extreme brilliance of Venus in an achromat usually causes all sorts of issues and almost any filter that dims the view helps.

Your relatively large 6” achromat could be used with a UHC for some deep sky observing.

As to the misty view you describe, this could be caused by - dewed optics, haze in the sky, nearby lights shining on the front objective, using a low power under a light polluted sky......or if you wear glasses they could need a clean 😊

A 6” achromat is a very useful instrument, so good luck with your new one 👍

HTH, Ed.

 

 

[SiriusB]

Been a bit of high haze here few nights recently, so maybe haze, probably some light pollution also, give it a bit more time to see if you get some better/ worse nights first.

I think there's probably better & maybe cheaper filters to use for planet contrast than a UHC, but as i only own 3 filters maybe someone better aquainted might chip in.

FWIW, i live in a town, it's not great skies but could be worse. If i lived in a city a big refractor would be my first choice of instrument. Others might disagree.... but it's certainly not a bad choice for urban Astronomy.

Ps, when the moons about, i think a look at that might clarify the haze situation .

[Don Pensack]

For planets, try a Baader Moon & Sky Glow filter, or if you're a Mars specialist, a Baader Contrast Booster (incredible on Mars).

But, haze in the sky does not help.

[Charlie 2436]

Thanks for all your advice. I will give it a few more nights to see if it was just atmospheric conditions on my first night. 
Is there any difference between sky glow and light pollution ?, and what is the best filter to combat them ?

 Thanks Robert 

[NGC 1502]

Hi Robert.  There’s not just 1 filter that helps with everything - if you could say what your main targets will be that would define better the most suitable filter.

Planets - there are specific filters to enhance what would be observed with your achromat refractor.

Deep sky - there are specific filters to help with some deep sky objects.

If your main problem is light pollution there are filters that are supposed to help - but divided opinions as to whether they are worth having.  Some would say the money is better spent on traveling to a better sky.

Ed.

[Don Pensack]

11 hours ago, Charlie 2436 said:

Thanks for all your advice. I will give it a few more nights to see if it was just atmospheric conditions on my first night. 
Is there any difference between sky glow and light pollution ?, and what is the best filter to combat them ?

 Thanks Robert 

Back in the '70s, light pollution was largely sodium vapor and warm incandescent lights.  Filters were created to cut out the yellow and orange parts of the spectrum to make the background sky a lot darker in the eyepiece so contrast would be improved.  Today's lighting is LCD, LED, halogen, fluorescent, neon, argon, zenon, arc lamp, various halogen, incandescent, and every variety of light imaginable.  As a result, light pollution is present at near every wavelength of the spectrum, so the broadband filters of the '70s are no longer effective at cutting down light pollution.  In fact, in bright environments, they scatter a lot of light inside the layers of the filter and make it worse.

They do work fairly well in dark skies to turn up contrast a tiny bit.

So in today's urban and suburban environment, a narrowband filter that passes only a few discrete wavelengths of light emitted by nebulae can be effective at making nebulae a lot more visible.  Since stars, galaxies, star clusters, and many other objects emit light at a lot of wavelengths, they are only helped by darker skies.  But at least for the brighter nebulae, nebula filters (narrowband, O-III, H-ß) can help reveal details and features and size of nebulae not visible without them.

But filters cannot help atmospheric haze, so wait for a clear and dry night.  Even here in Los Angeles, we can see stars to magnitude 5 on the clear, dry, moonless, nights.

[Charlie 2436]

Thanks for the advice Don. I was out last night and I noticed the sky seems to have a glow / haze to it , I guess that’s one of the drawbacks of living in a city. 
Don in what order of would you advise getting these filters ? Would I be as well going for Astronomik instead of buying cheaper and having to buy twice , also I know this might sound like a stupid question but do the 1:25” filters work just as well as the 2”.
thanks again Robert 

[Charlie 2436]

Hi Ed thanks for the advice, at the moment I would say that star clusters , nebula and some galaxies are my main focus ( no pun Intended 😁) . Any advice would be appreciated. I realise an achro might not be the best for star clusters.

 Thanks Robert 

[Pixies]

On 19/09/2020 at 11:26, Charlie 2436 said:

Thanks for the advice Don. I was out last night and I noticed the sky seems to have a glow / haze to it , I guess that’s one of the drawbacks of living in a city. 
Don in what order of would you advise getting these filters ? Would I be as well going for Astronomik instead of buying cheaper and having to buy twice , also I know this might sound like a stupid question but do the 1:25” filters work just as well as the 2”.
thanks again Robert 

Over to the east side of Scotland, the transparency had been pretty poor for the latter half of the week. Still air with a lot of moisture meant a haze and the sky was blue towards any light pollution, much like a northerly horizon in the summer. Actually, the still atmosphere meant that the seeing was great! 

[Don Pensack]

On 19/09/2020 at 03:26, Charlie 2436 said:

Thanks for the advice Don. I was out last night and I noticed the sky seems to have a glow / haze to it , I guess that’s one of the drawbacks of living in a city. 
Don in what order of would you advise getting these filters ? Would I be as well going for Astronomik instead of buying cheaper and having to buy twice , also I know this might sound like a stupid question but do the 1:25” filters work just as well as the 2”.
thanks again Robert 

You will use them at low powers (under 10x/inch of aperture), so whether or not you get 2" filters will depend on that.

I think 2" is the universal size, since it fits 2" eyepieces, 2" diagonals, and 2" to 1.25" adapters (most of them).

I would start with a Narrowband filter like:

Astronomik UHC

TeleVue Band Mate II Nebustar

Lumicon Gen.3 UHC

DGM NPB

Orion Ultrablock

Then, if your interest heads more to planetary nebulae, an O-III filter for maximum contrast. 

[LDW1]

On 17/09/2020 at 01:20, Charlie 2436 said:

Hi All I had my new 6” achro refractor out for the first time the other night and everything looked as if it was misty, l mean I could see the planets it’s just that the background was like a slight mist rather than black. Is this down to light pollution ? ( I live in Glasgow ) and would the Astronomik UHC filter help or is it just for viewing nebula.

 Thanks Robert 

I think you will find that UHC’s are designed to enhance some types of nebulas but may help other objects but their colors will be thrown off with dimmer views.

[LDW1]

3 hours ago, Don Pensack said:

You will use them at low powers (under 10x/inch of aperture), so whether or not you get 2" filters will depend on that.

I think 2" is the universal size, since it fits 2" eyepieces, 2" diagonals, and 2" to 1.25" adapters (most of them).

I would start with a Narrowband filter like:

Astronomik UHC

TeleVue Band Mate II Nebustar

Lumicon Gen.3 UHC

DGM NPB

Orion Ultrablock

Then, if your interest heads more to planetary nebulae, an O-III filter for maximum contrast. 

Don’t forget the Baader / Celestron UHC its a great filter that shows more back ground stars if you aren’t into the darker, back ground blocking filters

[Louis D]

10 hours ago, LDW1 said:

I think you will find that UHC’s are designed to enhance some types of nebulas but may help other objects but their colors will be thrown off with dimmer views.

The nebula colors tend to remain similar (still pretty much gray), but the surrounding star colors get a wonky red/green color to them that some people find very distracting.

[Don Pensack]

13 hours ago, LDW1 said:

Don’t forget the Baader / Celestron UHC its a great filter that shows more back ground stars if you aren’t into the darker, back ground blocking filters

The Baader UHC-S, reportedly the same as the Celestron UHC/LPR filter, has too wide a bandwidth to be a great nebula-enhancement filter.

If you don't want as dark a field, the filters with a 30-45nm bandwidth (usually also labeled UHC) would be better.

Don't get me wrong, as the Baader UHC-S is a great broadband filter.  I thought it was a bit better than my "gold standard" Lumicon Deep-Sky.

It works great on bright nebulae in truly dark skies.

But if the purpose is to enhance nebulae and the LP conditions are less than perfect, a narrower filter would work better.

[LDW1]

3 hours ago, Don Pensack said:

The Baader UHC-S, reportedly the same as the Celestron UHC/LPR filter, has too wide a bandwidth to be a great nebula-enhancement filter.

If you don't want as dark a field, the filters with a 30-45nm bandwidth (usually also labeled UHC) would be better.

Don't get me wrong, as the Baader UHC-S is a great broadband filter.  I thought it was a bit better than my "gold standard" Lumicon Deep-Sky.

It works great on bright nebulae in truly dark skies.

But if the purpose is to enhance nebulae and the LP conditions are less than perfect, a narrower filter would work better.

No question a narrower filter would be / is better to bring them out and I have a good selection of them but when I use my Celestron / Baader UHC, Baader is printed right on the Celestron filter holder, the views of the Orion, the Lagoon and others are pretty da*n nice with albeit a lighter background and more stars and less contrast but still a noticeable enhancement of the nebula. But what I am saying and have always said is that for the price they are a great change of pace if you want to get away from the same monotonous view with the narrower filters, that blacken out everything but the selected target, some like to see more background details, at times, while still enhancing  your target, I know I do, and that filter is the one, a great alternative ! And LP conditions are a key but I have never and will never say that narrower isn’t better overall, that UHC is just a nice change for some. The individual astronomers will have to make that decision, as always, I am just pointing it out. And many of the perfectionists, the technical observers can’t understand and / or accept it, from what I see, lol ! Just my way of sometimes looking at them, lol ! In the words of my old grandma ‘ a change is as good as a rest sometimes ‘ and I think this is one of them, its all part of the fun of this great hobby !  Clear Skies !

[LDW1]

7 hours ago, Louis D said:

The nebula colors tend to remain similar (still pretty much gray), but the surrounding star colors get a wonky red/green color to them that some people find very distracting.

The star colors aren’t that bad compared to say an NPB, now theres colorful stars but it too is a great filter, you just have to learn to look past them and at your target which does stand out well, much more so than the UHC I mentioned !

[LDW1]

Sometimes I just think of them as an in between filter that hangs between no filter and the better filters mentioned but they work and there is nothing wrong with that, its all that counts but if you don’t want to spend to buy one thats OK to !

[Charlie 2436]

Hi guys thanks for the advice. 
If I get a 2” filter and use it on the front of my 2” diagonal, so as I can use it with 2” or 1:25” eyepieces or does the filter need to be fitted to the bottom of the eyepiece .

thanks again for all your advice. 
Robert

[John]

You can put the filter on the end of the diagonal barrel or on the end of the 1.25 inch - 2 inch adapter, if it is threaded for filters. If you try the 2nd approach, make sure none of your 1.25" barrels will come into contact with the filter before attaching the filter.

 

[Charlie 2436]

Thanks for the advice John, much appreciated.

[Stardaze]

23 hours ago, Don Pensack said:

The Baader UHC-S, reportedly the same as the Celestron UHC/LPR filter, has too wide a bandwidth to be a great nebula-enhancement filter.

If you don't want as dark a field, the filters with a 30-45nm bandwidth (usually also labeled UHC) would be better.

Don't get me wrong, as the Baader UHC-S is a great broadband filter.  I thought it was a bit better than my "gold standard" Lumicon Deep-Sky.

It works great on bright nebulae in truly dark skies.

But if the purpose is to enhance nebulae and the LP conditions are less than perfect, a narrower filter would work better.

What's your go-to filter for Orion please? Be interested to know. 

[John]

11 minutes ago, Stardaze said:

What's your go-to filter for Orion please? Be interested to know. 

For me, either no filter or a good UHC such as the DGM NBP. I've used the O-III and H-Beta filters on Messier 42 to see the effects but on balance either no filtration or a UHC are my preference.

I'll be interested in Don's opinion as well of course

[Stardaze]

15 minutes ago, John said:

For me, either no filter or a good UHC such as the DGM NBP. I've used the O-III and H-Beta filters on Messier 42 to see the effects but on balance either no filtration or a UHC are my preference.

I'll be interested in Don's opinion as well of course

I was going to plumb for the TeleVue Nebustar II John. But wondered if that specific target would work better with something else.

[Don Pensack]

32 minutes ago, John said:

For me, either no filter or a good UHC such as the DGM NBP. I've used the O-III and H-Beta filters on Messier 42 to see the effects but on balance either no filtration or a UHC are my preference.

I'll be interested in Don's opinion as well of course

Pretty much agree.  I either use no filter or the DGM NPB on that one, though the Baader UHC-S adds just a bit of contrast enhancement and makes the image a tad better than no filter at all.

I don't disagree with LDW1--the Baader UHC-S is the only broadband in my filter box, and in dark skies it is my go-to filter for M20 because it doesn't kill the reflection nebula like the narrowbands do.

Normally, in dark skies, M42/43 is so bright it damages my night vision.  It's hard to see that a filter is needed, which is why turning up the contrast just a tad with the broadband works well.

When a nebula is as bright as M42/43, maximal contrast might not be needed.

The choice of filter can be an aesthetic choice instead of maximum contrast, even on the fainter stuff.  It depends.

Though a narrow O-III filter really is what is needed on NGC2359 (Thor's Helmet), I often prefer the view in the Baader UHC-S because the nebula sits in an incredibly rich area of the Milky Way.

Seeing the nebula seemingly hanging in space in front of thousands of background stars is a wonderful view, even if I pop in a narrow O-III to actually study striae in the bubble.

 

Different views require different filters.  I've whittled my filter collection down from 52 to only 13 now, but it's getting hard for me to decide which of the remaining ones have to go.

 

 

Edited September 25, 2020 by Don Pensack