57395Re: Dizzying Panoramas Of Stars In Motion
- Jul 29, 2014Am 29.07.2014 18:12, schrieb Keith Martin:
> Second, judging by the shot at the start that shows a large metal '+'You could even use a one shot solution. A circular fisheye pointed
> with the cameras mounted at the end of each arm, the cameras are much
> further offset than they need to be. Moving them as close together as
> possible would make the output more reliable.
straight up covers the whole sky, which would be perfect for long
exposures. And since those comet-like star trails are more or less
artificial anyway (normal star trails don't fade), one could think about
completely artificial trails.
As Helmut Dersch showed years ago
<http://www.panotools.org/dersch/startrail/trail.html> star trails are
straight and equally long in an equirectangular projection with the
zenith at polaris. So it should be easy to create "star trails" by a
simple motion blur of a sky panorama. (In fact it's not so easy, since
the trails darken due to blur. You need to duplicate layer with mode
lighten, shift 1px and flatten). This would reduce shooting to start and
end of the night in order to also cover stars that rise during the night.
Furthermore stars are colored. This is seldom visible, since stars show
as points which are overexposed very quickly while other stars are not
even visible. If you defocus slightly, stars are more like disks, which
don't overexpose that fast. Could be light pollution prohibits this - I
discovered it on altiplano in Peru 4000m above sea level and hundreds of
miles away from any city, one of the darkest regions on earth.
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