RGB filters and Moonlight

[MarkF]

Does moonlight have any effect on imaging with RGB filters? I know I could experiment but I am being lazy and drawing on more experienced people than me. Is RGB as effective as narrow band ie HA at cutting out light pollution, is RGB considered narrow band even?

[Breakintheclouds]

I'm sure more knowledgeable heads will be along shortly, but I would have thought that if you combine R, G and B channels, then you'll effectively have a record of all the visible light. So I wouldn't think this would really filter out any light pollution at all.

[Uranium235]

I was about to ask this very same quesion because im going to be buying my first set of filters soon. At first im just getting the Baader UV/IR block and a 7nm Ha (no filter wheel yet).

But.... what if i was to just stay with a hubble pallet? Are OIII and SII filters immune to LP too?

[MarkF]

OIII and SII are I believe true narrow band and will not pick up light pollution. I am intending getting them next, I was just curious about the RGB, not sure RGB is all visible light as that would be ROYGBIV, our sun is I believe a Green sun so impact could be seen on Green and probably yellow from reflected sunlight.

Guess I need to give it a whirl.

[FraserClarke]

RGB filters are considered 'broadband' filters. They have a width of hundred nanometers or more, compared ~10 nanometers for narrowband filters. RGB basically covers the entire visible range of the spectrum. The passbands are roughly;

B: 400-500nm

G: 500-600nm

R: 580-750nm

The exact numbers will depend on the filter set (RGB is not as well defined as the scientific UBVRI filters).

Yes, they will be affected by moonlight (and light pollution) much more than narrowband filters. Moonlight is quite blue, so B and G will be affected most, and R less so.

[MarkF]

Thks Tea Dwarf, so as Breakintheclouds said too, I stand corrected and am glad I didn't waste a few hours finding out myself on the rare clear nights.