FAQ/SouthernRotation

FAQ: Stars & the Southern Rotation

Why do stars rotate clockwise around Polaris and Counterclockwise and Clockwise around the South?

There was a lot of debate on the internet about this. It's extremely simple. So take a look at your car. When you witness a car drive forward from the outside, the driver side wheel always turns counterclockwise. The passenger side wheel always turns clockwise. The reverse is true if you are under the car. The same effect of rotations is true for a dome.

Look at the top of a lid and rotate it counter-clockwise. Now look at the rim. The rim appears to rotate clockwise! Everything goes from East to West in the sky. There also seems to be a huge debate in astrophotography that time-lapse videos of the "celestial south pole” is being faked. Some people claim they use special filters, dome cameras, wide angle, mislabeling shots of Northern Stars (or even simply CGI). Regardless, there is actually a lot of footage that conflicts with these time lapse instead showing the milky way and southern cross streaking across the sky in a slight curve and looks nothing like Polaris time lapse. The stars are said to have a 1 degree shortage in their rotation.

There was a brilliant video discussing this and the sidereal day. They showed pretty conclusively that the stars went east to west. There is other time lapse that shows stars moving streaking lines right besides spirals. In any case, it is completely possible to have this pattern (like a hurricane pattern in between the rotation with stars going above and below it). Like explained, the top of a dome will appear to rotate counterclockwise and the sides would appear to rotate clockwise. You can test this yourself by rotating a salad bowl. On the Azimuth map, Australia is on the opposite side to Africa and South America. So it is possible that there is a large spiral traced clockwise by the stars on each end.

However like previously stated many of these videos are in dispute. The distance of the stars would determine whether or not it would be easy to detect variations in the southern angle, after all, in the Azimuth map longitude lines are much large the further south you go. This plays a huge role in perspective of the stars. There are videos of crepuscular rays and anti-crepuscular rays which shows how the suns light angled up can rise in the horizon and the same theory has been applied to stars going across a dome pattern. When curving around a dome this can effect the way you see the stars. Also there have been other solutions and experiments proposed with rotating discs of projected light off a parabolic mirror however there are already many simple explanations.