NGC 2261

NGC 2261

NGC 2261
reflection nebula
An image of NGC 2261 by the Hubble space telescope.
Observation data: J2000.0 epoch
Subtype variable nebula
Right ascension 6h 39m 10s[1]
Declination +8° 45′[1]
Distance 2,500 ly
Apparent magnitude (V) 9.0
Apparent dimensions (V) 2′
Constellation Monoceros
Designations Hubble's Variable Nebula,[1] Caldwell 46

NGC 2261 (also known as Hubble's Variable Nebula or Caldwell 46) is a variable nebula located in the constellation Monoceros. It is illuminated by the star R Monocerotis (R Mon), which is not directly visible itself.

NGC 2261 was imaged as Palomar Observatory's Hale Telescope's first light by Edwin Hubble on January 26, 1949,[2] some 20 years after the Palomar Observatory project began in 1928. Hubble had studied the nebula previously at Yerkes and Mt. Wilson.[2]

One explanation proposed for the variability is that dense clouds of dust near R Mon periodically block the illumination from the star.[3]

See also


  1. ^ a b c "SIMBAD Astronomical Database". Results for NGC 2261. Retrieved 2007-04-11. 
  2. ^ a b
  3. ^ "A model for the cometary nebula NGC 2261". SAO/NASA ADS Astronomy Abstract Service. Retrieved 2010-11-28. 

External links

  • European Homepage for the HST – Hubble photos and information on NGC 2261
  • – Images by amateur astronomers
  • NGC 2261 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images