Bobsprit wrote:

Ones filters really cool a Nebula Line Transmission%
Oxygen-III 496mm90
Oxygen-III 501 nm85
H-beta 486nm88

I wish I could afford a pair of sunglasses made out of this stuff. The
ulta high contrast will blow your mind. Have any ideal what its for?

Some are for cutting out ambient man-made light of varrying types. Some work
well for photography, others visually. But remember that they also cut ALL
light by as much as 4 or 5%.

4 or 5% is bugger all.


Better to find a dark sky.

Always.

Cheers