Scorpius, Antares, and Globular Clusters

A quick moral mythology: Orion felt that he was such a great hunter that he once boasted to Artemis, goddess of the Wilderness, that he would kill every animal on earth. Rightfully unsettled by this proclamation, Artemis sent a scorpion to kill Orion before he could make good on his claim. The ensuing battle was epic.

Zeus, observing all of this from on high, snatched up the two duelists and placed them in the sky as a lesson to mortals forever to curb their pride. It is also said that Orion now hunts across the heavens for the winter months but is chased away every spring by the return of the scorpion.

As we enter the spring months of 2021, the scorpion is again rising in the eastern sky. This constellation consists of 18 main stars, one clearly outshining the rest. Antares is the 15th-brightest star in the sky, often called the “rival of Mars” from its visibly red hue.

A wide-field view with binoculars reveals a unique ball of light just 1.3 degrees west of Antares, known as Messier 4. M4 is a globular cluster, which initially will appear as a fuzzy cotton ball covering a swath of sky about the size of the Moon.

M4 was the first globular cluster to have individual stars resolved by astronomers in the 18th century. Having spent more than 250 years analyzing this dense gravity well, we now estimate over 20,000 stars are packed into an area just 27 light-years across. 

Once you locate M4 with your wide-field view, switch to a telescope or more magnifying eyepiece and you will begin to resolve some of the outlying stars and see how densely packed the center of this cluster truly is.

From M4, move slightly northwest to find another globular cluster. Messier 80 contains several hundred thousand stars spread across approximately 95 light-years. Despite having many more stars, M80 is less visible through binoculars due to its distance, at 3,200 light-years, as opposed to the much closer M4 at 7,200.