|Observation data: 2000.0 epoch|
|Right ascension||00h 40m|
|Distance||2.9 million light years|
|Apparent dimensions||21ˡ X 11ˡ|
|Other designations||Messier 110|
Discovery and observational data
A small companion of the Andromeda Galaxy, NGC 205 is easily found through even modest amateur telescopes in the immediate vicinity of Messier 31 itself. It is of a similar brightness to Messier 31's other satellite system, NGC 221 but because of its larger apparent size it is somewhat more difficult to see as the light from the object is spread out over a larger area of sky.
Charles Messier, a French comet-hunter of the 18th century, discovered NGC 205 in 1773 but did not at that time include it on his list of deep-sky objects. Ten years after Messier's discovery the galaxy was independently discovered by Caroline Herschel and William Herschel included it in his catalog a year later. It was added to the list of Messier objects in 1966 as an unofficial addition.
NGC 205 is classified as an E5 elliptical galaxy and is at a distance from Earth of some 2.9 million light years, similar to both the Andromeda Galaxy and NGC 221. NGC 205 is moving toward Earth at a speed of 241 km/s giving it a blueshift of -0.000804. The estimates of NGC 205's mass range from 3 X 109 and 15 X 109 solar masses. The galaxy was first resolved into individual stars by Walter Baade in 1944 when he observed both NGC 205 and NGC 221 as well as the central regions of the Andromeda "Nebula". NGC 205 is peculiar among elliptical galaxies in that it contains dust that indicate recent star formation.
- Frommert and Kronberg, SEDS, online at http://www.seds.org/Messier/m/m110.html
- IAU Circular 7240, August 19, 1999, online at http://www.cfa.harvard.edu/iauc/07200/07240.html#Item3
- IAU Circular 8272, January 20, 2004, online at http://www.cfa.harvard.edu/iauc/08200/08272.html#Item3
- Walter Baade, The resolution of Messier 32, NGC 205, and the central region of the Andromeda Nebula printed in the Astrophysical Journal, 1944