Eris
Tracking Eris
The image below shows a 5 minute guided exposure of Eris (indicated by arrow) taken on January 9 UT. The bright star in the upper right is SAO 12906. The plate factor is 0.95 arcseconds per pixel.
The dashed line represents a rough indication of the path of Eris from January 1, 2011 until about February 15, 2011. The period of time actually shows the retrograde motion of Eris - the time when it seems to move backwards in the sky due to the fact that the Earth is orbiting the Sun much more quickly than Eris. During this time the Earth was exactly 90 degrees from Eris on its path around the Sun.
A short report (pdf) (doc) describes the initial tracking of Eris at Bluebird Observatories.
