| Type | Multiple Star |
|---|---|
| Magnitude | 3.79 | Right Ascension | 5h 38' 44.8" (2000) |
| Declination | 2° 36' 0" S |
| Constellation | Orion |
| Classification | O9.5V+B0.2V(n) |
Andrew Cooper
Nov 26, 2022 Waikoloa, HI (map)
28cm f/10 SCT, NexStar 11" GyPSy @ 127x
Seeing: 6 Transparency: 7 Moon: 0%
A lovely group of stars centered on the bright blue-white σOri A, The 7th magnitude σOri D and σOri E components visible to the northeast and the somewhat fainter σOri C component visible 8" southwest. The notable Σ 761 group is visible 3' northwest including a nice 8th magnitude 8" pair.
σ Ori is commonly called a multiple star in many references, but a small cluster is probably a more appropriate description. While oddly not listed in one of the many cluster catalogs it can be found in literature as the Sigma Orionis Cluster or Sigma Orionis Association.
The σ Ori group is in a rich region 1° south of Alnitak, the entire area spectacular in the eyepiece.
| HD 294271 | HD 294272 | HD 294272A |
| HD 294272B | Sigma Orionis | Sigma Orionis C |
| Sigma Orionis D | Sigma Orionis E | Struve 761 |
Drawings, descriptions, and CCD photos are copyright Andrew Cooper unless otherwise noted, no usage without permission.
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