The Serpent-Bearer Ophiuchus is an ancient constellation that represents either Aesculapius, the founder of medicine, or Enkidu, the companion of the Sumerian hero Gilgamesh. In the media, the Serpent-Bearer keeps popping up as the 13th Zodiac sign every couple of years. Although the ecliptic passes through the constellation, it was never considered to be one of the signs of the zodiac. In 1604 Kepler discovered in Ophiuchus the last supernova which we could still observe in our galaxy.
70 Ophiuchi is a 16.6 light-years distant pair of two dwarf stars with about half the solar luminosity. Both 4.1 and 6.1m bright stars are separated by only 1.7 to 6.7 arc seconds and can therefore not be separated in binoculars. They orbit each other every 88.38 years – a further planet has not been confirmed yet. The stars show a nice color contrast in a telescope.
Barnard’s Star with a brightness of only 9.5m is an object for larger binoculars, and even then it can be identified only with the help of a good star chart. The only 140,000 miles (225,000 kilometers) big red dwarf star shines only with 1/2500th of the brightness of our Sun and despite a distance of only 5.94 light-years it would not be worth mentioning if it wouldn‘t have the highest apparent proper motion – every year it moves around 10.3 arcseconds almost exactly north. Within 175 years, its position thus changes by about a full Moons diameter. In 3,800 years it will come close to the solar system up to 3.8 light-years, at which time it will stand near the head of the Serpent.
M 10 and M 12 are two closely adjacent globular clusters, which are 3.5° apart and therefore fit together in the field of view of binoculars – a nice sight. M 10 is 6.6m bright and only 14,000 light-years away. The moderately concentrated globular cluster has a slightly more eye-catching core than the weaker concentrated M 12. M 12 is about 17,000 light-years away and thus a real neighbor of M 10. Both globular clusters are about 12 arcmin in diameter and can only be resolved into individual stars with a telescope.
M 19 appears in the binocular as an oblate patch of light. This 6.8m bright globular cluster is 34,500 light-years away and has a diameter of only 5 arcmin. Along its main axis, there are twice as many stars as in its minor axis.
The globular cluster M 62 is exactly in the galactic plane and can easily be seen in binoculars as a seven minutes of arc long light spot, which is brighter towards the center. It even appears twice as large in photographs. The 20,000 light-years distant globular cluster is 6.5m bright.
The Pipe Nebula (B59, B65, B66, B67 and B78) is a 2 × 7° large complex of several dark nebulae that extend over several hundred light-years. Especially in the pipe stem you can see some structure in binoculars. The nebula belongs to the ρ Ophiuchi complex and is about 600 light-years away.
Northwest of the pipe head is another dark nebula, the S- or Snake Nebula (Barnard 72), which can be seen with about 11x magnification. It extends over approximately 30 arc minutes and can only be seen easily if you have a very dark sky.