Category Archives: Star Clusters

Messier 21 (NGC 6531): A Compact Open Cluster in Sagittarius

Messier 21, discovered by Charles Messier in 1764, is a compact open star cluster in Sagittarius. At approximately 3,900 light-years away, it contains 57 stars and offers a unique beauty, especially when viewed with binoculars or a telescope. It resides near the Trifid Nebula, making it a notable observation destination.

Messier 7 (NGC 6475): Ptolemy’s Ancient Cluster Still Shines Bright

Messier 7, or Ptolemy’s Cluster, is a prominent star cluster located in the Scorpius constellation, first recorded by Claudius Ptolemy in 130 AD. This open cluster, visible to the naked eye, contains 80 stars and spans 25 light years. It symbolizes the lasting human fascination with astronomy and the cosmos.

Learn more about the cluster, including a personal observation from Wayne McGraw and photo using a Seestar S50 under suburban skies in Florida.

Messier 25 (IC 4725): A Scattered Jewel in Sagittarius

In the 18th century, Charles Messier cataloged celestial objects while searching for comets, including the beautiful open cluster Messier 25 (M25) in Sagittarius. Approximately 2,000 light-years away, it contains around 600 stars with no nebulosity. M25 is best viewed through binoculars or low-power telescopes during summer nights, offering a delightful starry tapestry. Also known as M25, IC 4725, Melotte 202

The Coathanger Asterism: A Cosmic Clothes Hanger in the Summer Sky

The Coathanger asterism, located in the constellation Vulpecula, is a distinctive pattern of ten stars resembling an old wire hanger. Initially described by Al Sufi in the 10th century, it’s not a true star cluster but an asterism. Ideal for binocular viewing, it’s perfect for casual stargazers. Also known as Brocchi’s Cluster and cataloged as Collinder 399.

NGC 1758: A Hidden Gem in Taurus’ Starry Landscape

NGC 1758 is a lesser-known open star cluster in the constellation Taurus. Discovered by William Herschel in 1785, it is approximately 700 million years old. Though not visible to the naked eye, it provides valuable insights into stellar evolution. Its proximity to NGC 1750 poses observational challenges.

NGC 2451: A Stinging Scorpion Down South in Puppis

NGC 2451, a star cluster in the Puppis constellation, shines brightly during late autumn and winter. With around 40 stars, including the prominent C Puppis, it’s visible with binoculars. The cluster is an optical illusion of two separate groups. First noted by Hodierna in the 17th century, NGC 2451 offers a captivating viewing experience.