M5 in Serpens Caput is a refreshing sight through a small telescope, as thousands of stars cluster together into the tightly packed ball of this globular cluster.

Bruce McClure

Kelly Kizer Whitt

June 6, 2025

Alphecca, a jewel in Corona Borealis the Northern Crown

Alphecca. Gemma. Alpha Coronae Borealis or simply Alpha Cor Bor. They're all names for a single star, the brightest star in the Northern Crown.

Bruce McClure

Deborah Byrd

May 30, 2025

Look for equinox shadows in a direct line from west to east

Equinox shadows are unique. On this day - and only this day - the tip of an upright stick's shadow follows a straight path, west to east, all day long.

Bruce McClure

March 18, 2025

Look for amazing Omega Centauri, using Spica as a guide

Omega Centauri is the largest globular star cluster visible to the eye alone. In the spring, the star Spica can lead you to the giant globular cluster.

Bruce McClure

March 14, 2025

Meet Taurus, home to 2 fabulous star clusters

Taurus the Bull resides near the constellation Orion the Hunter. It contains 2 famous star clusters that are easy to spot; they are the Pleiades and the Hyades.

Bruce McClure

February 6, 2025

The mass of a star is determined from binary star systems

Binary stars - a star system consisting of two stars - are extremely useful. They give all the information needed to measure mass of a star. Here is how.

Bruce McClure

Theresa Wiegert

January 31, 2025

Sirius is a future southern Pole Star

Wait, what? It's true. The sky's brightest star, Sirius aka the Dog Star, will come to within 1.6 degrees of the south celestial pole in the year 66270.

Bruce McClure

Editors of EarthSky

January 30, 2025

Bruce McClure

Bruce McClure served as lead writer for EarthSky's popular Tonight pages from 2004 to 2021, when he opted for a much-deserved retirement. You can still find many articles at EarthSky.org that were originally written by Bruce, and which the EarthSky editors still update regularly. Bruce is a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also wrote and hosted public astronomy programs and planetarium programs in and around his home in upstate New York. Bruce he loves cycles of all kinds! You can still find many articles at EarthSky with Bruce's name on them, exploring the various, intricate cycles of the sky.