LP Filters - your experiences

[acey]

Good luck with the filters it'll be interesting to hear how you get on.

I've used a Lumicon UHC for years and I find it's the only filter I need. But it's only useful on emission nebuale (eg Orion, Veil, Ring). Fortunately there are lots of emission nebulae in the sky, so it's worth the investment.

The filter lets through OIII and H-beta emission lines and nothing else: nebulae emit strongly at those wavelengths so the filter helps improve contrast against the sky. On anything else (stars, galaxies etc) it simply makes them fainter. Equally, the filter won't help on reflection nebulae (eg M78 or the Pleiades nebulosity).

A pure OIII filter should have much the same effect as a UHC. A filter designed solely to transmit H-beta is useful on only a few objects, notably the Horsehead Nebula.

Old-fashioned streetlights emit at sodium wavelengths and these can be filtered out using a light-pollution filter. But most places nowadays have high-pressure sodium, plus white domestic lights, etc etc, and they can't be filtered out (unless you filter out all the starlight too). So most people find light-pollution filters to be of little use.

A nebula filter will work against light pollution - but only on emission nebulae. So for anyone trying to do deep-sky observing from a site polluted by high-pressure sodium light, I'd recommend getting a UHC and concentrating on emission nebulae. I've used my filter on scopes of 80mm, 200mm and 300mm aperture, and it's equally good on all of them.

[ashenlight]

acey, thank you for this, made for interesting and informative reading. I've got a lot of cloud cover in my area for the next couple of days but here's hoping that Sunday night will be clear, as predicted. Will let you all know how I got on in a review thread in the Equipment Discussion forum.

Amanda

[greenkat]

Seeing as you're doing English poetry at uni, we want the report in a Shakespear styleee

[Astronut]

From the opinions and reviews I've read so far, I think the wider band-pass filters such as neodymium, etc aren't much use visually but they seem to be effective for imaging. The only filter I've got is the Astronomik UHC and while it helps increase contrast on emission nebulae eg, veil, M27, etc., it's no good on clusters, galaxies and anything that emits light across the spectrum. I expected this before I bought it and it was no surprise.

Oddly, I've found it to be more useful and effective at a dark site. Even though the UHC is a narrow bandpass filter (not quite as narrow as an OIII), it's not very effective as a light pollution reduction filter.

Consequently, I'm not convinced wider bandpass general-purpose light pollution reduction filters work effectively for visual use in the light-polluted sites that most of us have to contend with. It's probably the light pollution itself which cuts across the whole visual spectrum. If the LP were just low-pressure sodium street lighting then maybe they'd work better but put white floodlights, high-pressure sodium lighting, lighting from windows, office buildings, factories, industrial estates, etc. in the mix and there's the problem.

[ashenlight]

greenkat, I'll write it as a traditional Petrarchan sonnet

Astronut, that is interesting - I'm really eager to find out if these work for me now. It was cloudy the other night but I held each filter up to my eye to see if it muted the orange glow in the clouds - they both did, but the Skywatcher seemed to maintain good contrast between muted clouds (which now looked 'night time cloud colour' and the dark blue sky that wa speeking through. The Baader didn't do quite as well, and still showed hints of the tell-tale orange glow in the brightest clouds. We shall see! I haven't even viewed any emission nebulae yet, my main interest was to try and improve the conditions when viewing the globs and galaxies that I have viewed so far.... so I will just have to see. I'll just go with what I view as the best and then keep my fingers crossed that it performs on emission nebulae aswell.

Cheers guys

Amanda

[Starobserver]

Hi Amanda,

Here's a little on my experiences with light pollution filters. I have both the Lumicon Deepsky filter and the Baader Skyglow. I observe from my lightpolluted backyard most of the time (about 95% of my observations, so I was very interested in these filters at first. What they both do is make the overall view a bit darker, but to be honest, on all deepsly objects, including galaxies and globulars they don't have any effect visually. I have not used both for more than 2 years.

However there are two filters that work definitely, the UHC and the OIII, but they only work on emmission nebulae and planetary nebulae. And they work in both light polluted areas and real dark sky areas, but again there is a difference. In the light polluted areas these filters make the difference between not seeing the objects at all or very faint, and just sseing them. When used at a dark place, the objects sometimes jump out at you when using a filter. So they seem to work better in dark places.

And what do I think of all these filters in the end. Well, to be honest the UHC, OIII (and for very few objects the H-Beta) bring out more details, show some parts of the nebulae better, and I use them every now and again, but......... aesthetically, I prefer the unfiltered view in most cases, however that's very personal of course. Steve Coe, who wrote a few books on deepsky observing, stated in one of his books, that he tried all the lumicon filters, but did not like to use them at all.

So thats all I can tell you, and from my own experience I can say: try them before you buy them.

Hope this helps.

[Taff]

Hi Amanda' the one on FLO is the one i have got a 2''.I find the filter useful for the LP and it does it's job.Mark

[ashenlight]

Thankyou Math, still waiting for a decent night to get out there and try them out. Taff, which one is it you have, the Skywatcher of the Baader?

[coliea]

Following the thread Amanda and looking forward to your comparison. Hope you get a break in the clouds soon.

Col

[coliea]

I found this related CN thread interesting:

Telescope Reviews: Thinking about filters, but are on a budget?

[athlon]

I use an Astronomiks CLS EOS clip infilter for imaging, and it does a great job, whereas exposures would be washed out with orange fog within about 3-4 mins, this does a great job of blocking out unwanted light, although it leaves a slightly blue tinge on the image, i only mention this as they do a standard version for eyepieces as well, and it should perform just as well.

Here in Australia dark sky's are never very far away. Although i remember the first 36 years of my life (born in UK) where filled with tango orange skys that washed out all but the brightest stars.

good luck on whatever you decide to choose.

[ashenlight]

Hi guys,

See my thread regarding the LPRF here

It's very simply testing but it has worked for me.