Astronomy Picture of the Day (timelapse with Earth rotating) | Hacker News Reader

Astronomy Picture of the Day (timelapse with Earth rotating)

apod.nasa.gov

69 pointslostbit15 comments

Flying over the north pole at night, my United 777 once flew perfectly anti-rotation for a while, and then non-rotation when over the axis-pole. the moon and stars never moved for over an hour - as the pilot pointed out.

Hold onto the grass so you don't fall off! :)

Strange how some of those segments made me a little queasy.

Beautiful. Our galaxy is pretty. I wish it could be seen a little more like this with the naked eye.

Nice idea. But they only used 2D translation and rotation. Ideally they would have used a homography (projective transformation). Unless other effects are ruling the image (radial distortion, atmospheric diffraction) this should lead to a better result.

The camera is turning at an angular speed of 7.2 × 10^-5 rad/s which is the speed of Earth's rotation.

I'm confused. This is a timelapse video. So shouldn't the camera appear to be turning a little bit faster than that?

The idea of the video was to remove Earth rotation from the view. This removal was digitally made.

One of the original videos used in this compilation - with the traditional "sky is moving" feeling - is this one: http://vimeo.com/22439234. It's the best, in my opinion.

Thats why I said the camera "appears" to be turning, because it isn't actually turning. Sorry, I may have phrased that badly.

But thank you for the link. It's a great video.

camera isn't turning... they just rotated all the images the camera took to keep the sky fixed in position.

What was the deal with that laser? What could they possibly be aiming at?

Read about [Adaptive Optics](http://en.wikipedia.org/wiki/Adaptive_optics) -- The telescope watches the laser beam and corrects for atmospheric distortions.

Excellent new look that reminds us that the Stars are not spinning. A reminder that we need to get off this spinning rock asap.

Excellent new look that reminds us that the Stars are not spinning.

Yes they are.

A reminder that we need to get off this spinning rock asap.

Why?

Because it is just one of trillions of spinning rocks, subject to the same concerns than any particular grain of sand on any given beach would be.

If we want our species to survive, we need to be more than occupiers of a single grain of sand.

As to the first point, I think the poster was meaning that the stars' movement is not the main cause of the nightly patterns across the sky, the earth's movement is.

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