Scorpius: the constellation of the scorpion

Scorpius is a constellation that has made me wish so many times that i could live in the southern hemisphere, as this constellation is only fully visible between the latitudes of 44 degrees North and 90 degrees South. From where I live in the UK Scorpius is just visible on the horizon in the summer evenings however, as it is so low in the sky i never get to appreciate all its wonders, and there are many…

firstly, Scorpius lies just outside the centre of our galaxy, the milky way. this means that the constellation is home to many star clusters, several of which are visible to the naked eye. such star clusters include M7 or the Ptolemy cluster which was named after the Roman/Greek academic who is known to have first described it in AD.130. M7 is an open star cluster which can be seen by the naked eye as a bright clump of stars in the milky way, although it is best observed through binoculars. It has a magnitude of 3.3 and is widely considered to be one of the best deep sky objects in Scorpius due to its brightness and it’s size as it is more than twice the apparent size of a full moon. It is located near to the tail of Scorpius and next to another open star cluster, M6, the butterfly cluster, which is twice as distant and hence, appears much fainter than M7.

Open cluster NGC 6231.

Open cluster NGC 6231. (Photo credit: Wikipedia)

another open star cluster of interest is NGC 6231 or the table of Scorpius. this is a very young open star cluster thought to be only 3 million years old, which consists of around 100 stars. this cluster, which has a magnitude of 2.5, is around 5,900 light years away and again is visible to the naked eye as a tightly knit group of stars. however when viewed through binoculars or a small telescope, the individual stars of this cluster become visible which makes for an amazing sight.

Scorpius is also home to the 16th brightest star in the entire night sky, Antares. This star is a super-giant that has a diameter of around 800 times that of the sun, which means that if it was placed in our solar system then it would extend beyond the orbit of Mars. Antares’ brightness is slightly variable and fluctuates between magnitudes 0.9 and 1.2 every four to five years. Antares translates into ‘rival of Mars’ as Ares as another name for Mars, the Roman god of war.

Scorpius is an interesting constellation as it never appears in the sky at the same time as the constellation of Orion, the hunter. In Greek myth, this is because Scorpius and Orion were great rivals and were always fighting which caused a lot of disturbance amongst the gods. therefore, the gods decided to put a stop to the fighting by separating Scorpius and Orion by putting them in opposite parts of the sky. so you can be sure that if Orion is in the sky, Scorpius is nowhere to be seen and when Scorpius appears Orion will disappear. Have a look on a planisphere and you will see that these two constellations will never share the sky.


  • information on the constellation of Scorpius sourced from ‘stargazing for beginners’ ISBN: 978-1-4053-6195-8
  • information on the myth of Scorpius and Orion was soured from my own knowledge.

One comment on “Scorpius: the constellation of the scorpion

  1. Pingback: Exploring the constellation of Hercules | Astronomy, geography and more

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