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.
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.
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.
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.
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.
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.
When a year with 366 days starts on a Monday, it's inevitable Friday the 13th will occur twice. In 2024, Friday the 13th comes in September and December.
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.