Archive

Archive for October 24, 2025

Ephemeris: 10/24/2025 – How to spot the Double Cluster

October 24, 2025 Comments off

This is Ephemeris for Friday, October 24th. Today the Sun will be up for 10 hours and 32 minutes, setting at 6:42, and it will rise tomorrow at 8:11. The Moon, 3 days past new, will set at 7:55 this evening.

This pair of objects are about as dim as one can see with the naked eye, but very rewarding for binoculars or small telescope, the Double Cluster. It’s a fine pair of star clusters just below the W of the constellation of Cassiopeia the queen located in the northeast.  Draw a vertical line down from the middle star of the W through the next star into the glow of the Milky Way.  The Double Cluster appears to the unaided eye as a brighter glow of the Milky Way.   This is confirmed with binoculars.  But in a small telescope it becomes two clusters of sparkling diamonds.  The clusters are much younger than the Sun, so their brightest stars are blue-white to our eyes.  The average distance of the two from Earth is 7,500 light years.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

A finder for the Double Cluster showing the sky, looking northeastward at 9 PM tonight, October 24th. Created using Stellarium, LibreOffice Draw, and GIMP.
Double Cluster by Daniel Dall'Olmo
The Double Cluster. Both clusters can fit in the field of a 50 power telescope eyepiece. Credit: Daniel Dall’Olmo.