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Old 18-August-2006, 11:58 AM
grant hutchison grant hutchison is online now
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Quote:
Originally Posted by max8166 View Post
So to position the moon in the longitudinal sense, in other words ignoring the latitude. Can I say that for every earth day (24 hours) the moon moves about 13.179 degrees ** in the sky? (just in the longitude plane)
Afraid not.
1) Because the moon has an elliptical orbit, it moves alternately faster and slower across the sky.
2) When the moon is far from the celestial equator, it will cross more lines of celestial longitude for a given angular movement than it does when it's near the equator: the lines of longitude are closer together (as they converge towards the pole), and the moon is moving more nearly orthogonal to them.

Grant Hutchison
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