β Ophiuchi

Beta Ophiuchi is a yellow giant, the second brightest star, nine degrees south of alpha, and a little to the east.

There is quite a lot in this binocular field: a famous red dwarf, an open cluster that Messier missed, and a binary with a pleasant colour-contrast.

The famous dwarf is Barnard's Star, which is the fastest star in the heavens; that is, its proper motion, 10.358", is the greatest known, as it appears to slowly but perceptibly climb higher (northerly) in the skies.
      Barnard's Star is a red dwarf with 9.54 visual magnitude; it is 5.94 light years away, making it the closest to the Solar System after the alpha Centauri triple star system. Burnham's Celestial Handbook, p. 1252, has a location map.

Just a little over a degree northeast of beta is a little-known open cluster known as IC 4665.
      Composed of about thirty stars, with an apparent magnitude of 4.2, this is a fine binocular object; the cluster is about 35 million years old.

The star on the southwest edge of your viewing field, 61 Ophiuchi, is a binary (Struve 2202) with subtle colour-contrast—a white primary and bluish-white companion: 6.1, 6.5; 93º, 20.6".


Move a little over a half binocular field southeast, and you'll have 70 Oph nearly centred.
     70 Ophiuchi is a fine telescopic binary (Struve 2272) with a lovely colour-contrast: 4.2, 6.2; 130º, 5.9" (The primary is yellow-orange, the companion reddish-orange.) The orbit is 87.71 years. There are ten components all together in this system, mostly quite faint.

The neighbouring star about a degree northwest, 67 Ophiuchi, is a binocular double, (BU 1124)AC: 4.0, 8.1; 142º, 54.2".

Slightly more than four binocular fields due west is lambda Ophiuchi.

Click on lambda on the map to continue.

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