Apparent motion due to parallax

The two images in this animation were taken at exactly the same time (2010-Oct-08, 0600 UTC), one from the remotely controlled telescope in Cambridge, MA, and the other from the remotely controlled telescope in Arizona.  You can see the difference in the comet's apparent position from the two locations due to parallax.  The apparent motion is about 38 arcseconds.  Using 2600 miles as an approximate figure for the distance between the locations gives the comet's estimated distance as 14.1 million miles -- pretty close to the actual distance of 13.9 million miles at the time of these observations.  Thanks to Frank Sienkiewicz of the Center for Astrophysics for scheduling the taking of the two images used in this animation.