Double pairs in Scorpius
The quadruple star system Nu Scorpii requires a good view towards the horizon and calm air. Then, with larger telescopes, the stars can be resolved.
ν Scorpii is a quadruple star system, which is often compared to the Double Double ε Lyrae. The first pair can be resolved with just 25 times magnification: a magnitude 4 component resolves at a comfortable distance (41") from its slightly fainter magnitude 6.3 companion. Both components also have companions, but their resolution is much more difficult and requires a much larger aperture.
With a 200mm telescope and 200 times magnification, a third component could be surmised but could not really be successfully resolved. So the observer needs not only a good view of the horizon, but also a lot of patience.
Low on the horizon
ν Scorpii is located at a declination of –19°, about as far south as M41. If you are already able to observe this open cluster close to the horizontal in constellation Canis Major, then you can venture on a summertime excursion to Scorpius. Antares is a suitable starting point, which can be seen over the horizon in the summer months together with the stars at the scorpion’s pincers, π, δ and β Scorpii. If you are in the city, with luck you may be able to exploit a gap between buildings. The advantage is that ν Scorpii is relatively easy to find: from β Scorpii, the northernmost of the three pincer stars, the telescope only needs to be panned 1.5° to the east to a prominent triangle consisting two magnitude 7 stars and one of magnitude 4 star. The brighter star is our target: ν Scorpii.
Horsehead Nebula in Scorpius
When a Horsehead Nebula is mentioned, everyone immediately thinks of the distinctive object in the constellation of Orion. Few people are aware that there is also a nebula in constellation Scorpius, whose shape also resembles a horse’s head: IC 4592. This nebula is particularly distinctive due to its predominantly bluish colour. Located on the nose of this horse, star ν Scorpii, is responsible for the colour. However, you’ll need a very dark sky and a southern location in order to see the Blue Horsehead Nebula close to ν Scorpii.
Author: Karl-Peter Julius / Licence: Oculum-Verlag GmbH