I'm directionally dyslexic but I belive the moon was moving left to right. ------------------------------ On Wed, Apr 16, 2014 9:37 AM MDT Seth Jarvis wrote:

Hi Dion,

Yes, Earth's shadow definitely drifts slowly right-to-left.

It's not just that the Moon is orbiting the Earth. Other motions are involved.

Simulating the eclipse in Starry Night I see a significant shift in the relationship between Earth's shadow and the background stars depending on your lat/long, so I'm guessing that there is a parallax effect produced by Earth's rotation that would cause a shift in where the shadow seems to be as observers rotate with the planet.

Also, when you "freeze" your location and isolate yourself from Earth's rotation (e.g. hovering above the North Pole) there's still a slight but noticeable drift in the shadow relative to the stars - because we're in motion around Sun.

Seth

-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Dion Davidson Sent: Wednesday, April 16, 2014 9:04 AM To: Utah-Astronomy@mailman.xmission.com Subject: [Utah-astronomy] Eclipse: moving shadow?

I am working on processing some images from the Quarry Bend star party of the eclipse: https://picasaweb.google.com/lh/photo/PfMBXArypRaGS_8Yzq_tMbjs7i-NclWSB9dbXw...

I'm surprised that when I align the stacked images on Spica, not only does the moon move right-to-left, as expected, it seems the earth's shadow moves left-to-right. Is that real? Why would that be? 

n the image linked above you can see how the moons on the right lay over top of the shadowed portion of the next moon. I expected to see a nice earth-shaped shadow in the middle of the image once all the photos were aligned. These were taken with my Nikon D7000 riding piggy back on my telescope (fork-mount on a wedge), 10 minutes apart.

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