How long does it take the Big Dipper to move in the sky?
What length of time is required for the Dipper to change from one position to the other?
It depends on which is the "one position" and which is the "other position". :)
In the Northern Hemisphere, all of the stars appear to rotate about a point in the sky that is due north, and at an elevation equal to the latitude at which you're standing. This also happens to be the point in the sky occupied by the North Star. (The same thing happens in the Southern Hemisphere, but there things rotate about a point in the south.)
This apparent rotation of the sky is actually a result of the fact that the Earth itself is rotating. So the sky does one complete rotation every 24 hours. Of course, you can't see the stars during the day, but the sky is still "rotating" then nonetheless.
So you see, there aren't just two positions for a constellation like the Big Dipper. But over the course of an entire night (~12 hours), you should be able to see it move from one end of its "path around the North Star" to the opposite end.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 29386 times since March 9, 2003.
Last modified: March 9, 2003 2:46:02 PM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)