Hello,
Having enjoyed some success in imaging Nereid (moon of Neptune) and Pluto, I decided to venture deeper into our solar system, beyond the dark reaches of Pluto, to capture Eris (Minor Planet 136199), lying at some 2.4 x the mean Pluto-Sun distance. Current estimates for the diameter of Eris are in the range 3100 - 9900 km with an orbital period of 560.2 years.
Eris currently lies in the constellation of Cetus, shining at a dim magnitude of 18.74 some 8.93 billion miles (14.37 billion kilometres) from the Earth. When first discovered Eris was labelled as 2003 UB 313 and classified as a Minor Planet but with the demotion of Pluto, it is now a Dwarf Planet! The discovery of Eris was announced on January 5, 2005 based upon images taken on October 21, 2003.
SkyTools 3 Pro gives the following (sub-set) details about Eris:
R.A.: 01h41m05.2s Dec.: -04°22'04" (2000) in Cetus.
Apparent RA: 01h41m35.7s, Apparent Dec: -04°18'58"
Magnitude: 18.74
Orbit Period: 560.2 years
Perihelion Distance: 38.4 AU
Aphelion Distance: 97.5 AU
Current Status:
Earth Distance: 96.1 AU
Sun Distance: 96.7 AU
Total motion: 21.0 "/day
RA: -17.15 "/day
Dec: -12.16 "/day
Information sourced from:
http://www.wolframalpha.com/
SkyTools
Cheers
Dennis
PS – the reason that Eris is off-centre is that my ST7 is the older parallel model with the TC211 guide chip (192x164 pixels) and sometimes finding a bright enough guide star doesn’t allow for centering the main object on the (765x510 pixel) imaging chip.
