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Barnard’s Loop


Proper NameBarnard's Loop
Messier NumberNone
NGC/IC NumberNone
Other DesignationsSh2-276
Right Ascension (centre)5h 27m 30s
Declination (centre)-3° 58' 0"
DistanceHighly uncertain; between 500 and 1,400 light years
(160 to 440 parsecs)
MagnitudeApparent: +5.0
Absolute: -1.0 to -3.2, depending on distance
Mean DiameterApparent: 10°
Actual: 100 to 300 light years, depending on distance
Optimum VisibilityDecember / January

A ring of matter that occupies the central region of Orion. It is thought to be caused by the active regions of Orion's Belt, and is immense in extent. It is more than two hundred light years across, and almost surrounds the famous shape of the Hunter in the night sky. The Loop is too faint to be detected with the naked eye.

This image of the southern parts of Orion is filtered to highlight ionised hydrogen, making Barnard's Loop stand out distinctly as a wide 'C'-shaped structure. The two bright areas within the Loop represent the Orion Nebula (to the south) and the complex nebulosity around the star Alnitak in Orion's Belt (to the north). Imagery provided by Aladin sky atlas


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