Future of Light Pollution Reduction Filter

[Akira]

The level of air pollution and cloud must also be factors - if the air were clear then there would be nothing for the light to illuminate and it would just pass out to space?

Good point.  Unfortunately, however, the air pollution over Tokyo (and I would bet this applies virtually all big cities) is bad enough for various particles in the air to reflect the light coming from the city to cause light pollution.


Ilkka, Hugh, and Colin, thank you for chiming in.

Not only the satellites but also the airplanes flying over big cities are not-so-minor annoyance that ruin the night photography.  I hope the directional control (downwards) of LED lights will be more sophisticated to reduce the meaningless radiation into the sky.

Colin, no worries about straying!

[Øivind Tøien]

Reflectivity of the ground also has strong influence on effective light pollution. I see an increase in background exposure at zenith of up to two EVs once there the snow comes on the ground and in the trees - only a smaller part of that is the haze/ice fog (vs. that clear air in the fall). So there is a rather narrow window of really good conditions - snow typically stays on the trees until it melts in early spring time, which improves things a little.  On top of this we have the "light pollution" from the aurora, that tend to be more frequent around equinoxes in fall and spring...

I thought I was going to have a good imaging session on the Veil nebula the other night, but it took longer than expected to get it going, and once I got outside again for my first check, I found that clouds suddenly had drawn over after only 19 minutes. Planets are getting better these days, so that is an alternative when light pollution get too troublesome, although seeing is another matter then.

[Akira]

Reflectivity of the ground also has strong influence on effective light pollution. I see an increase in background exposure at zenith of up to two EVs once there the snow comes on the ground and in the trees - only a smaller part of that is the haze/ice fog (vs. that clear air in the fall). So there is a rather narrow window of really good conditions - snow typically stays on the trees until it melts in early spring time, which improves things a little.  On top of this we have the "light pollution" from the aurora, that tend to be more frequent around equinoxes in fall and spring...

I thought I was going to have a good imaging session on the Veil nebula the other night, but it took longer than expected to get it going, and once I got outside again for my first check, I found that clouds suddenly had drawn over after only 19 minutes. Planets are getting better these days, so that is an alternative when light pollution get too troublesome, although seeing is another matter then.

Hmm...I forgot about the reflection of the snow.  Simply because I've never seen the aurora, I would rather welcome it, but it surely will a major hindrance for the astrophotography.

[Akira]

The sky happened to be very clear (for Tokyo) Tonight and I tried to direct the camera roughly toward the Orion near the zenith.

And here is a resulted image and its 100% crop of the area of "The Belt" and the Horsehead nebula.

I know this is a quite crude image to call an astrophotography, but I was pleasantly surprised by the number of stars captured.

Sigma fp, Lumix S 50/1.8, ISO3200 0.8sec f2.2.  I only used Nikon Arcrest protection filter to avoid any dust, because I directed the camera upwards.  The image was processed more heavily than the normal ones I've been posting here but not too much.