Filters for a skywatcher heritage 150p (6" dob)

[going-supernova]

Hi.

After finally getting a clear night after what feels like months off cloud cover I finally managed to take my skywatcher heritage 150p (virtuoso) scope outside again for a spot of observing. 

I'm a beginner and my current goal is to target some nebulae.

It was a very chilly night so i focused on m42 as my first target using my svbony 7-21mm and it was beautiful to see.  I was able to make out some of the nebula structure and zoom in on the Orion Trapezium Cluster.

I've since  been looking into getting a filter to get a clearer view of the nebula and future nebula tagets.  From my googling so far it points me at purchasing a uhc filter.

As there are a few options on the market I was hoping to get some opinions from anyone with a similar scope on the benefit of a uhc filter and whether the more expensive Astronomik UHC Filter (£89) would be worth getting over a Explore Scientific UHC Nebula Filter (£47) or Castell UHC Ultra High Contrast Filter (£38).

These seem to be the ones which come up time and again on forums but any opinions on other filters for nebula observation for this type of scope would also be welcome and greatly appreciated. 

Thank you

[Astro_Dad]

I’ve been enjoying M42 also with the Heritage 150p over the past couple of clear nights. I’ve tried a basic UHC filter on it and it does provide a good view - showing for example the trapezium stars as a blue-green. I’ve also compared with a Baader OIII filter. At 6” the UHC for me provided a better view as is a broadband filter so still offers a fairly bright view  - but, and it’s a personal view, I find Orion better without a filter. The UHC is regarded as a good all round nebula filter though and works well on other targets. 
the one I have is:

https://www.firstlightoptics.com/uhc-oiii-visual-filters/uhc-filter.html

I don’t have experience of other more expensive filters, but I am sure others can comment on the relative quality increase as you pay more. 

[Zermelo]

I'd agree with @Astro_Dad: with my 150mm I prefer M42 without a filter. Other nebulae respond much more to filters; for example I've only ever seen the Veil with a UHC.

The OIII is a "narrower" filter, it passes a smaller amount of the available light. So on my modest scope I have had more success with the UHC. Though you can improve your views with any filter by selecting an eyepiece that gives you a larger exit pupil, i.e. with lower magnification - assuming your target is large enough to still be seen.

As to which brand of filter, well I haven't been going long enough to compare myself, but Astronomic arnd Lumicon are generally well thought of.

[cajen2]

I have the same scope. The only filter I have so far is a Baader Neodymium, which for me certainly makes the nebulosity in M42 clearer.

[John]

I have the Astronomik UHC in the 2 inch format and it is pretty good. I've read that the Castell UHC is a decent performer as well but I've not used that one. I've tried a few lower cost UHC's that were not all that effective though. One surprise filter has been an older Meade 4000 Narrowband Nebular (spelt like that !) which is a UHC type and works rather well. I think that cost around £25.00 used.

The Orion Ultrablock was another decent one that I used to own. I've heard that the quality of those can be variable though. I must have had a good one !

I have to add that I did have an Explore Scientific UHC for a while recently and found it rather mediocre in terms of contrast enhancement.

 

[Astro_Dad]

2 hours ago, cajen2 said:

I have the same scope. The only filter I have so far is a Baader Neodymium, which for me certainly makes the nebulosity in M42 clearer.

That’s interesting @cajen2 - I’ve never thought to try my Baader Neodymium on M42 as I bought that primarily for contrast enhancement for certain planetary views. I’ll give that a try though. 

[cajen2]

Well, contrast enhancement between a diffuse cloud and an LP sky....🤔

Someone on here said the Baader is the "Swiss Army knife" of filters (sorry, can't remember who to give credit).

[Louis D]

The Baader Neodymium cuts out a good chunk of the yellow part of the spectrum where there is a lot of light pollution.  This also increases the contrast between blue-green and red-orange planetary features much like a magenta or salmon filter operates.

[Astro_Dad]

I don’t have too much light pollution here as Bortle 4, and it’s mainly the odd LED  light interfering at times which filters of course don’t help with - the Baader should as suggested though boost contrast against natural sky glow. I tried it late last night (early hours) during a brief gap in the clouds, after reading the suggestion here, and was indeed a good view. Still have preference for no filter on M42 but I’m going to try it again on my 8 inch. The Baader was recommended to me quite some time ago (yes as the Swiss army knife!) just haven’t really road tested properly yet other than on Jupiter, where it does give some improvement. 

[John]

I've owned a couple of Baader Neodymium filters over the years but didn't keep them for long because they didn't seem to do much, at least to my eye

When I use a filter to observe a nebula (I prefer not to mostly) I want it to make a really noticeable difference and for that I've found the good quality O-III and UHC tick that box for me.

 

[Franklin]

Both the UHC and OIII filters from Castell are effective and probably the best of the budget options, IMO.

[Franklin]

2 hours ago, John said:

I've owned a couple of Baader Neodymium filters over the years but didn't keep them for long because they didn't seem to do much, at least to my eye

The Neodymium is a very subtle filter and originally intended for reflecting telescopes and true apochromats. It does reduce sky/moon glow, rendering the background sky a little darker and therefore boosting contrast, though I have to agree it is a very slight improvement. Baader have since combined the Neodymium with minus violet filters for use in achromats and semi-apo ED doublets, these are their Contrast Booster and Semi-Apo filters. I've tried them all and think the Contrast Booster has the most effect. I think, from what I've read online, that the Neodymium is effective when used for imaging as a light pollution filter and it was proven to tighten up star images. The review I read was on the Baader and Company 7 websites.

[bomberbaz]

A UHC is generally seen as the best all round filter,. especially with smaller aperture scopes.

If you don't want to spend a shed load of cash then the svbony UHC is both cheap and effective although more broadband than narrowband according to this thread where the filter was actually tested.  Svbony Uhc Flter - Equipment - Cloudy Nights

However if you have the cash, both the televue and astronomik are £ for £ the best filters, on tests for transmission my information is the TV just shades it but at such small % you are unlikely to notice the difference. 

[mr_belowski]

i got an Astronomik UHC filter for my 8inch Dob. Under Bortle 6(ish) skies it's a bit of a disappointment - obviously i need to fix my expectations but in the conditions I've tried it in, it's not really worth the money

[John]

I have an Astronomik UHC (2 inch) and I'm quite happy with it. I use an O-III when I want a more substantial impact though. I've tried some less expensive UHC filters that have been very modest in their performance - the Astronomik is a noticeable step above these.

Of course you need to pick a receptive target and use an appropriate exit pupil to get the best out of these narrowband and line filters.

My skies are around Bortle 5.

 

Edited January 9, 2022 by John

[RT65CB-SWL]

The Baader neodymium is my ‘Swiss-Army knife’ filter. I also use the Explore Scientific UHC and Olll.

[cajen2]

I also bought the Astronomik UHC filter and found it somewhat of a disappointment on M42. The view was rather dark and I didn't find the nebulosity much improved - the Baader did a better job. I need to try the UHC on other nebulae, but I feel it needs a larger scope / better light-gathering abilities than mine.

[Pixies]

32 minutes ago, cajen2 said:

I also bought the Astronomik UHC filter and found it somewhat of a disappointment on M42. The view was rather dark and I didn't find the nebulosity much improved - the Baader did a better job. I need to try the UHC on other nebulae, but I feel it needs a larger scope / better light-gathering abilities than mine.

Wait till you get the new dob!

[cajen2]

2 hours ago, Pixies said:

Wait till you get the new dob!

Mmmmmm, it's the waiting that's so difficult...!