light pollution filters

Hi,

There are several light pollution filters on the market, some broadband, some narrowband, some seem specific to mercury, some specific to sodium, and some manage to do a bit of nebula enhancing on the side.

I understand the optics of these filters, and can compare the spectra profiles etc. but does anyone have any first hand opinions on which is best for combatting the typical Dublin sky glow? If they enhance nebulae all the better, but my primary concern is to cut skyglow down, even it if darkens the image a lot.

Cheers,
~Al (going shopping)

albert,
i got the meade broadband filter last year. it was not hugely expensive and i really just got it as i did not want to spend too much in case it did not really work out. i was happy with the purchase. for nebula it works well. it does make they sky darker. i did not try it on any clusters yet. if you are looking just to dip your foot in the water it could be the way to go. considering when looking to the south i have more of dublin to look over than you i think it still would work well for you.
stephen.

Hi,There are several light pollution filters on the market, some broadband, some narrowband, some seem specific to mercury, some specific to sodium, and some manage to do a bit of nebula enhancing on the side.I understand the optics of these filters, and can compare the spectra profiles etc. but does anyone have any first hand opinions on which is best for combatting the typical Dublin sky glow? If they enhance nebulae all the better, but my primary concern is to cut skyglow down, even it if darkens the image a lot.Cheers,~Al (going shopping)

Al,

On a very general basis, the consensus is that Broadband LPR filters are only useful from seriously light polluted city areas and not of any great benefit from less light polluted suburban areas. Anyway, you've a few choices on Broadband filters, which do aesthetically improve views by darkening the background sky more than objects but do little if anything to actually reveal any more detail or bring objects into view that you couldn't see before. So, they are not a cure for light pollution, they just make things look better by increasing contrast. The Orion SkyGlow, Celestron LPR, Meade Broadband and Lumicon Deep Sky are four examples. I've only experience of the Meade and Celestron filters (I own a Celestron LPR) and there is little difference. I find it reasonably useful at times from my light polluted suburban garden. Phil Harrington's table in Starware suggests the Orion SkyGlow and Lumicon Deep Sky filters are _slightly_ better with the Sky Glow getting the final nod.

Narrowband filters are not really light pollution filters but are designed to enhance emission and planetary nebulae and will do nothing for stars, clusters or galaxies. Examples of Narrowband filters are the Orion UltraBlock, Meade Narrowband, Lumicom UHC, Lumicon OIII and Baader UHC. I have the Meade Narrowband (SCT version) which works best under dark skies but again, PH's table suggests the Orion UltraBlock and Lumicon UHC are slightly superior. I'm going to try a Baader UHC soon.

So, while I'm happy enough with the Celestron LPR when I do choose to use an LPR filter (not too often), you may be better off getting the Orion SkyGlow.

Gordon

Al, Hutech also do the IDAS LPS filters, I believe these work quite well, but also are a bit on the expensive side. It's all down to what you want

www.sciencecenter.net/hutech/idas/lps.htm

www.sciencecenter.net/hutech/filtlist.htm

Also here in the UK:

www.scsastro.co.uk/it220002.htm
Good Luck,
Keith..

Hi ,
According to lumicons site, their IDAS filter gives a superior light curve when used with a 300D, visually I'm not sure?
For photography, just keep in mind that you're reducing the overall image brightness, thus you'll need to track longer then you would without any filter be it light pollution reducing or not, so any mount issues will be exaserbated.

Is there a real noticeable improvement in using a light pollution filter? I've priced a few, and they seem quite expensive. You see, it's my birthday coming up and I'm about to start dropping hints to 'er indoors about what I want! I was thinking of, at this point in time, just getting a set of colour filters instead -would these be better for seeing DSO's? BTW, budget for the LPR, not more than £100...