How to Find the M5 Globular Cluster (One of the Best Clusters In the Night Sky)

Learn about the M5 globular cluster, one of the most beautiful things in the night sky. Globular clusters are ancient clusters which were formed before the galaxy itself existed, lying within the milky way's halo, which surrounds the galaxy.

Unlike open clusters like the Starfish Cluster, which disperse over time, globular clusters such as those in the summer triangle stay tightly packed for billions of years. The M5 cluster is thirteen billion years old making it one of the oldest globular clusters. The formation of globular clusters is poorly understood, but they are believed to evolve slowly over time. Globular clusters are attributed to areas with a lot of star formation and a dense interstellar medium, but after the cluster is formed there seems to be no further star formation.

There is something majestic about globular clusters, like the M5 globular cluster, which shows so many stars packed together.

In fact, this cluster has always been a favourite of observers since it was discovered and was referred to by Admiral Smyth as … Superb object … a noble mass, refreshing to the senses after searching for faint objects, but you will need high powers to have the same result for yourself!

So, what do you need to see M5?

Shining at magnitude 5.7, M5 is one of the brightest globular clusters in the night sky and is visible to the naked eye under dark skies as a faint point of light.

With binoculars, it is easily visible as a small fuzzy patch.

A small 80mm or 3.1-inch telescope reveals a nebulous ball with a bright core.

Individual stars in the cluster can be resolved under excellent dark skies using a 100mm or 4-inch telescope, the brightest being of 11th magnitude.

How to find M5?

Click to enlarge M5 star chart
M5 is located in the Serpens constellation and the best time to see it is the months of March, April, and May. To find M5 first go to the Boötis constellation, which is supposed to resemble a herdsman. This constellation also contains the fourth brightest star in the sky, Arcturus. From Arcturus, head to Zeta Boötis in the herdsman's right leg and from there hop down to 109 Herculis in the constellation Hercules. Then across to 110 Herculis and keep on heading in the same direction using a low power eyepiece to scan the area for the globular cluster.

To see what the cluster should look like through a 150mm or 6-inch telescope please watch the episode below.

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