Virgo and Her Treasures

Although Virgo is the second largest constellation in the sky (after Hydra), it is poorly known to casual skywatchers. That’s because it contains only one first magnitude star, Spica, and its other stars do not form an easily recognizable pattern like the Big Dipper or Orion.

Virgo is the second largest constellation by area, and is well placed just after dark for exploration. Credit: Starry Night software.

Most of the stars which form the pattern of Virgo are third or fourth magnitude, so are hard to see unless you have dark country skies. City dwellers will need binoculars to see them. Starting from bright Spica there is a chain of four stars to its right, with Porrima (Gamma Virginis) in the middle the brightest. Two stars extend northwards from Porrima, ending with Vindemiatrix.

 Porrima is one of the finest double stars in the sky, but has been hard to split in recent years because the apparent distance between its two components had been closing. It is once again opening up, and its separation of slightly more than 2 arc seconds makes it easy to split in all but the smallest telescopes.

 There are two other double stars in neighboring constellations worth a look: Algorab in Corvus and Zubenelgenubi in Libra, which can be split in binoculars.

If Virgo has few bright stars it makes up for it by containing more galaxies than any other constellation in the sky. It is most famous for containing the Virgo Galaxy Cluster, the nearest galaxy cluster to our own Local Group. Located 60 million light years distant, this is the richest cluster of galaxies in the sky.

The Virgo Galaxy Cluster is an easy starhop from Vindemiatrix. Credit: Starry Night software.

You can locate the Virgo Cluster by sweeping first westward from Spica to Porrima, and then northward to Vindemiatrix. Five degrees west of Vindemiatrix is Rho Virginis at the center of a distinctive Y-shaped group of stars. The Y points upwards to the galaxy cluster. The problem with the Virgo Cluster is not spotting the galaxies, but trying identify which is which. This chart <> will help you to follow the starhop and identify the galaxies. The secret to observing galaxies is to view them from a location with dark skies on a moonless night.

Charles Messier in the Eighteenth Century observed and catalogued eight galaxies in this cluster, plus six more just across the border in Coma Berenices. Two more Messier galaxies are outliers from the main Virgo Group, Messier 49 and Messier 61.

The final Messier galaxy in Virgo is one of the brightest galaxies in the sky and lies slightly nearer than the rest of the Virgo galaxies, 50 million light years distant. This is the famous Sombrero Galaxy, number 104 in Messiers catalog. It can most easily be found by following a starhop which starts at Gienah, the upper right star in Corvus. In binoculars you can see a long chain of stars extending northeastward from Gienah, ending in a small triangle followed by a group of stars shaped like an arrow. The arrow points right at the Sombrero Galaxy.

This starhop from Gienah in Corvus will lead you directly to the Sombrero Galaxy, Messier 104. Credit: Starry Night software.

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