Amateur images of Cis and Trans-Neptunian objects

The term Trans-Neptunian object (TNO) is used to describe those objects that orbit the sun at a greater average distance than Neptune. TNO's are rarely imaged by amateur astronomers because - with the obvious exception of Pluto - they are extremely faint. Few get brighter than magnitude 19!

Various sub-divisions of TNO's exists.

TNO Targets for the DART group

Name Type Image
Haumea Classed as a plutoid, that is a dwarf planet beyond the orbit of Neptune. Its status as a dwarf planet means it is presumed to be massive enough to have been rounded by its own gravity, but not to have cleared its neighbourhood of similar objects. Haumea may be in a 12:7 orbital resonance with Neptune. Click here

Huya is a dwarf planet candidate and is classified as a plutino orbiting in a 2:3 resonance with Neptune. Huya has an estimated diameter of 530 km.

Click here
Ixion Ixion is in a 2:3 orbital resonance with Neptune and so is a plutino. It is also a potential dwarf planet. Click here
Makemake Makemake is the second brightest TNO's and is classified as a dwarf planet and as a plutoid. Click here
Orcus Orcus is a large plutino (an object in 2:3 orbital resonance with Neptune). Click here
Quaoar Quaoar is a potential dwarf planet orbiting the Sun in the Kuiper belt. Click here
Varuna Varuna is a large classical Kuiper Belt object (KBO), a cubewano and a potential dwarf planet. Click here

The term Cis-Neptunian object is used for all sub-planetary bodies orbiting the Sun between the orbits of Jupiter and Neptune including the icy asteroids known as centaurs and the Neptunian Trojans.

CNO Targets

Name Type Image
2060 Chiron A centaur that also shows cometary activity - hence classified as both an asteroid and a comet. Pending
60558 Echeclus A centaur that also shows cometary activity - hence classified as both an asteroid and a comet. Click here
52872 Okyrhoe Suspected of showing cometary activity. Pending
95626 2002 GZ32 A Uranus-crossing asteroid. Click here
120061 2003 CO1 A bright centaur (magnitude 19.5!) Click here

Martin Nicholson - Daventry, United Kingdom. The image was taken using the facilities provided by the Sierra Stars Observatory Network (SSON).

This page was last updated on February 5th 2011.