In October, 2012, CAV imaging maverick Joe Mize threw down the gauntlet and challenged us to image the most distant trans-Neptunian objects -TNOs (of which Pluto is one) in the Solar System. The website with the challenge is below (I only read the part in English). This site lists the 3 currently farthest TNOs known ranging in magnitude from 18.7 (Eris) to 21.4 (2007 OR10). I had to wait until an appropriate weekend to get clear skies to tackle Joe’s faint-challenge TNOs but Oct. 6th was clear and beautiful at CAV so I remotely loaded the database from Harvard into The Sky for all 3 objects and went after the faintest 255088 2007OR10, which my database lists at magn. 21.5 (see chart above)! This object is in Aquarius near the meridian (and near Neptune) at around 11PM EST. I did three 30-minute luminance exposures at -10C, easily violating the privacy of this most secretive TNO! Is nothing sacred?
http://www.astrosurf.com/asanz/TNO.htm – Fantastic Distant Faint TNO Challenge