Comparison of 3 light pollution filters

[markarian]

Having just got an Astronomik EOS clip CLS filter (from Modern Astronomy), I thought I would compare it to the other 2 that I already have - a 2" Skywatcher LP filter and an old (about 1989) 2" Lumicon Deep Sky Filter. Not had a chance to use the new one in anger yet, but this is a sequence of 25s exposures using an old fixed 135mm lens on a 350D (unmodded). Had to use this lens as you can't use EF-S lenses with the EOS clip.

The existing 2 filters had to be mounted in front of the lens and therefore have some reflections going on, but I think you get the idea. (Some focus issues too perhaps which I will need to resolve to do this properly next time). I should say that this is for the sepcific types of street lights around the western edge of Edinburgh. The combination of lighting will be different where you are so you can't really expect the same results.

1. No Filter

2. Skywatcher (£25)

3. Lumicon (about £125 - but >20 years ago - current price £170 - but new ones will probably be better than my old one)

4. Astronomik (£107)

The Skywatcher has the least colour shift but filters out the least. However, I have found it to be less aggressive than the Lumicon and useful on star clusters - but hard work when there is any nebulosity around.

The Lumicon is pretty good and similar to the Astronomik in terms of transmission and colour shift, but the clarity of the Astronomik and extra image brightness is what surprised me. This could be partly due to where the filter is mounted? Looking forward to trying it in anger now.

Interested to hear your views. Thanks

Mark

[tiwar]

I assume these are for photography? Excuse the silly question, so much to learn!!

T x

[markarian]

Well the Skywatcher and Lumicon ones are 2" fittings so can be used for visual - although I don't usually. Astronomik fits inside a Canon EOS camera so imaging only.

[Leegsi]

Is it possible to put the prices next to what filter so its easy to see the difference in cost aswell as filtering?

[markarian]

Added prices now as requested. Remember, the Lumicon is very old and I'm sure the new ones are better now.

[Albireo380]

Interesting comparison, Markarian. I have just bougt an Astronomik CLS clip filter from Modern Astronomy also. I managed a few subs at 2.5mins each on M45 last night, before the clouds rolled in.

Stacked using DSS then a bit of tweaking in CS2, and all seems well (apart from the "mushy" focus).

The EOS CLS clip filter certainly cuts out the orange glow.

Tom

[astronymonkey]

Really good to be able to see the difference side by side.

Is there any chance you could do the same with a Deep Sky object so we can see the difference there ?

Ive been thinking of getting a filter and this does show that there is a vast difference. I suppose you get what you pay for but I understand what you mean about them possibly being better in some circumstances,

Cheers,

Astro

[riklaunim]

SkyWatcher works like Baader Neodynium - it cuts only a bit of the LP emission lines to improve contrast. Except IDAS LPS filter all other ALP and UHC filters just cut the whole orange/yellow spectrum so high pressure sodium lamps are totally cut out - at the cost of dimmer view and altered color.