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Old 12-07-2009, 01:19 AM
Rob_K
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Join Date: Oct 2006
Location: Bright, Vic, Australia
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Nice one Dennis, very clear!


Quote:
Originally Posted by M54 View Post
Is that Pluto's movement around the Sun that we can see?
I didn't know it would be noticable in such a short time span.
Most of the apparent movement in Dennis' shots is a parallax effect of Earth's orbital movement I think. If Pluto had a circular orbit (which it doesn't) it's movement viewed from the Sun (and Earth is close enough to that relative to Pluto's extreme distance) would be around 0.6 arcseconds per hour based on a period of nearly 250 years, or less than a pixel in Dennis' shots. Of course with its elliptical orbit its orbital speed varies, but not enough to account for the movement shown in the shots.

Cheers -

Rob
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