Light Pollution Filters

[AstroTiger]

In a word, are these any good?

Sky at Night mag is offering them with their subscriptions, i am considering re subscribing to the magazine with this in mind.

(yes i do also want the mag)

but are these filters any good?

You comments greatfully recieved.

[LukeSkywatcher]

I have a SkyWatcher LP filter. Cheap as chips but works really well.

[AstroTiger]

Thanks luke,

i will likely subscribe and try it. See how it goes :-)

Thanks for that

[Llamanaut]

I'm thinking of subscribing too... What's the effect of a filter like? Is it lifechanging or subtle?

[LukeSkywatcher]

I'm thinking of subscribing too... What's the effect of a filter like? Is it lifechanging or subtle?

I can only report on my experience with the SW LPF that i bought from FLO.

I did an "extreme" road test with the filter when it arrived. I attached it to all of my EPs in turn and pointed my scope directly above and in between two orange light street lights across from my house.

Without the filter i could see a few stars against an orangy/black background.

With the filter i could see a lot more stars which were brighter against a really dark background.

I'm not talking about "dark sky" dark background but it was heading in that direction.

That was out the front of my house.

From the back garden which is sheltered from any street lights...........the SW LPF performs outstandingly. My back garden does suffer from LP from a nearby dual carraigeway (about 2Km away) etc but with the LP filter..........................its almost non-existant.

Soooo

Is the difference life changing or subtle?

With the filter i have it is a lot more then subtle but i dont think it is "life changing".

The difference is VAST.

P.S.~~~the SW LPF also works amazingly as a moon filter................if you dont already have one. It shows lovely contrast on lunar features even when the moon is full.

2 birds...........1 stone.

[Rui]

It also depends on the telescope size. In a small refractor or reflector, the filter may take too much light and dim the field of view.

Remember the filter cuts some light wavelenghts and galaxies and stars emit in the whole spectrum. So some of the light from the celestial objects is cut as well.

[LukeSkywatcher]

It also depends on the telescope size. In a small refractor or reflector, the filter may take too much light and dim the field of view.

Remember the filter cuts some light wavelenghts and galaxies and stars emit in the whole spectrum. So some of the light from the celestial objects is cut as well.

Yes that may be true but LP filters are designed to only cut certain light emissions from those pesky streetlights........which are on a different level to celestial objects.

LP filters only job is to block the orange sky glow from streetlights.

They do that.

When you look at night sky objects with a LP filter in place..............they appear brighter because the light from them is not fighting light pollution here on Earth.

Thats MY experience

[Rui]

Indeed the object seems easier to view. It's an effect of contrast. Although the celestial object is slightly dimmer, the background gets darker, so the contrast increases.