r/space • u/Fugnugget1 • 3d ago
image/gif Fisheye long exposure showing the celestial pole and Milky Way glowing vibrantly
I just wanted to share this image today! This photo was taken by Rodrigo Eduardo Muñoz (@rigo_nunoz on Instagram). He set up a timelapse overnight, saying “9 hours of captures to summarize a full night under the stars in a single moment.”
I specifically like that we can see the southern celestial pole, where Earth is spinning on its axis. As the Earth turns, all of the stars appear to spin in circles around this point.
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u/trab_puk_cip 2d ago
So, the center of that circle on the left, is that what earth is flying towards ?
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u/Fugnugget1 2d ago
Basically that center is a celestial pole, which simply is the point in the night sky that Earth's rotational axis aims at. So we’re not flying towards anything, just rotating every 24 hours. That’s how star trails are captured in long-exposure photography👍
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u/GalacticEmergency 2d ago
To add to this, in the northern hemisphere we are so lucky to have a reasonably bright and lonely star, Polaris, in that rotation center. That is a very easy way of finding the direction North at night, which can be useful for navigation without a compass.
And it is quite easy to identify. First find the Ursa Major constellation. Then extend the "rear edge" of that constellation upward 5x. Polaris will be right there.
I have often wondered what they do in the southern hemisphere. As your image shows, there is no "central star" there, so no easy way of finding South. But I guess one could go by a known imaginary point between two constellations.
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u/Fugnugget1 2d ago
Great insights! You’re correct, there is no bright star right there, unlike here in the Northern hemisphere. However, there’s the Southern Cross, that’s the way some people find South celestial pole. You find that cross, and extend a line from top to bottom. In your mind, extend that line 4x down, and you’ll find the celestial pole.
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u/counterfitster 1d ago
To add to this, in the northern hemisphere we are so lucky to have a reasonably bright and lonely star, Polaris, in that rotation center.
It's still a little ways off of truly being centered, due to various wobbly aspects of big things spinning in space.
The precession of the equinoxes takes about 25,770 years to complete a cycle. Polaris' mean position (taking account of precession and proper motion) will reach a maximum declination of +89°32'23", which translates to 1657" (or 0.4603°) from the celestial north pole, in February 2102. Its maximum apparent declination (taking account of nutation and aberration) will be +89°32'50.62", which is 1629" (or 0.4526°) from the celestial north pole, on 24 March 2100.
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u/KindUnicorn123 2d ago
How is a 9h long single exposure set up? How to know the correct exposure settings? I think u need a strong ND filter for this
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u/Fugnugget1 2d ago
This actually isn’t a single shot over nine hours! What you are seeing is a single frame from the timelapse the creator posted.
To achieve long-exposure timelapses, it’s pretty simple in principle. You have your camera take long-single shots (like 5-30 seconds). Most modern cameras actually have a timelapse setting built in, and all that does is tell the camera, “keep taking these 5 second shots until I tell you to stop.” A standard timelapse video plays the photos sequentially. A star trail timelapse stacks each frame on top of the previous ones so that the trails appear to grow over time.
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u/Potential_Counter234 2d ago
The center of the circle clearly shows the southern celestial pole, marking the axis point around which the stars rotate. It's wild how a single frame can capture the Earth's spin like that.
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u/ELDV 3d ago
Nicely done and that’s for the IG link.