NGC 2261

9.0 may

2 '

2.5 kly

NGC 2261, Caldwell 46

NGC 2261 ( Hubble 's Variable Nebula and also Caldwell 46 ) is a variable reflection nebula in the constellation of Monoceros. He is illuminated by the star R Monocerotis (R Mon), but which is itself not visible.

NGC 2261 was described as " first light" of the Hale telescope by Edwin Hubble on 26 January 1949 photographed. Hubble studied the mist already at the Yerkes and Mount Wilson Observatory.

A thesis for the variability are dense dust clouds around R Mon, periodically blocking its light.