Delta Orionis (Mintaka)

δ Orionis and the Belt
Delta Orionis (Mintaka: "The Belt") forms the left end of Orion's belt (or right-most of the three central stars as we look at them). The three stars of the belt follow the Greek alphabet: delta, epsilon, zeta, and are best viewed in binoculars as all three nicely fit in the same field of view: binoculars.

Delta is a fine binocular binary (BU 558) of a white primary and blue companion, AC: 2.4, 6.8; 0º, 52.4".

Epsilon (Alnilam - The Belt of Pearls), the central star of the belt, is a supergiant surrounded by a wispy nebulosity which generally permeates through the entire constellation.

Zeta (Alnitak, - The Girdle) is very similar to Epsilon, except that this star is a very fine triple system (Struve 774):
      AB (light blue, orange - although observers disagree): 1.5, 3.7; 167º, 2.3" orbit
      AC: 1.9, 9.6; 10º, 58.0". (This may only be optical.)

Half a degree south of zeta is the famous ‘Horsehead Nebula’, the best representative of a dark nebula. It takes long exposure photos to bring out the famous features; it's invisible in telescopes.

South of the belt are three oustanding binaries, two of which are significant multiple star systems.

Eta Orionis is a fine telescopic double of two white stars: 3.6, 4.9; 77º, 1.8".

Sigma Orionis is a vast multiple system (BU1032) of which the first five are readily accessible—discounting the closeness of B:
      AB: 4.1, 5.3; 81º, 0.3" orbit
      AB-C: 3.8, 8.8; 240º, 10.7".
      AB-D: 3.8, 6.6; 84º, 12.9".
      AB-E: 3.8, 6.3; 62º, 41.3".
      AB-F: 3.8, 7.9; 324º, 209.6".

When viewing sigma, it is only natural to find this little gem of white stars 3.5' south of sigma: Struve 761, also a multiple system:
      AB: 7.9, 8.4; 203º, 67.8".
      AC: 7.9, 8.6; 209º, 71.7".
      AD: 7.9, 11.9; 309º, 32.9".

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