Light Pollution Filter

Light Pollution Filter


In stock - Shipped 1-2 working days.

Model:  SW_LPR_filter-1
Part Number:  20198
Brand:  OVL


This contrast-enhancing anodized aluminium, optical glass filter is designed to block out the wavelengths of light emitted by mercury-vapour light and other common causes of light pollution, whilst providing higher transmission at critical hydrogen-alpha and hydrogen-beta lines than competing filters.

Bright, light-polluted skies appear darker, and the contrast between object and sky is improved significantly. This contrast-enhancement effect is particularly apparent on nebulae. Unlike stars, emission nebulae give off light in a very narrow range of wavelengths. The filter allow maximum transmission of the important wavelengths of H-alpha, H-beta and doubly ionized oxygen – the ones most commonly emitted by nebulae.

Views of galaxies and star clusters are also enhanced, but to a lesser degree. Also improves contrast on reddish planetary detail.

Works well in telescopes of all apertures but is highly recommended for use on smaller telescopes up to 114mm diameter, where conventional filters swallow up too much light.

Available in two sizes, threaded to fit either standard 1.25” or 2” astronomical eyepieces.

Supplied with storage case. 

There are currently no specifications available for this product.

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Average Rating (4 Reviews):  
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Rating (max 5):  
Does what it should
Monday, 7 May 2012  | 

A really good filter and although I have the 2" version I do not doubt that the 1.25" is just as good. A good value alternative to the more expensive filters.

Rating (max 5):  
sodium killer
Sunday, 29 January 2012  | 

In my location on the south coast we have horrid old sodium orange lights of the old sling it in all direction sort,having nearly given up using a dslr as 2 min + exposures you end up with a bright orange pic,even down to 1 min you still see the intrution,after using the 1 1/4 size the images are pure black,totally taking out the false colour,have ordered a 2in version also flo do a one piece adaptor(no more bits unscrewing and cameras doing there own thing)in the past have used sw direct connection but this does not allow the addition of any form of filter,if your in a sodium light area these are superb,as other reviewers say maybe not for all light types.

Rating (max 5):  
Saturday, 21 May 2011  | 

The filter works well for light pollution, though only for the light from the orange sulphur street lights on these it does work very well.

It also cuts down the general skyglow as well, which is very welcome.

Rating (max 5):  
Either awesome or poor depending on your light pollution
Thursday, 19 May 2011  | 

This is a good filter but it's performance will vary from miraculous to a damp squib depending on the type of light pollution you are facing.

If you're observing through city light pollution, don't expect much improvement. There's just too much light for the filter to block out. If the filter blocked out all that light you wouldn't see anything at all.

However, if you have old street lights, the deep orange low pressure sodium ones - this filter will do an excellent job of cutting that out. It works too on the higher pressure sodium (still orange) lights but not quite as well as these lights are brighter.

As for floodlights, security lighting, etc, these filters won't do much.

I highly recommend these filters for all observers using 1.25" eyepieces. If you're in England, you really need one of these in your eyepiece box. If you're in a city, they're helpful too in case you travel outside. I've tested this filter from two English star parties from relatively dark skies and they did improve the views, increasing contrast and dulling down the orange glow from nearby towns.

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