This Week’s Sky at a Glance, 2025 Aug 23 – Aug 30
This Week’s Sky at a Glance, 2025 Aug 23 – Aug 30
From late summer into autumn, the Greek tale of Perseus and Andromeda plays out on the eastern stage of the night sky each evening. Princess Andromeda, the daughter of Cepheus and Cassiopeia, is chained to the rocky coast of Ethiopia as a sacrifice to a vicious sea monster, portrayed by the constellation Cetus the Whale. Our hero Perseus, on his way home aboard Pegasus after beheading Medusa, rescues the princess and wins her unchained hand in matrimony.
The constellation Andromeda consists of two lines of stars stretching toward Perseus from a common point. That point is the bright star Alpheratz, which is officially Andromeda’s head but it also forms one corner of the Great Square of Pegasus. The bottom line of stars is more prominent, containing the orange star Mirach and ending with Almach, which resolves as a pretty double star in a small scope.
The highlight of the constellation is M31, the Andromeda Galaxy, the nearest spiral galaxy to our own Milky Way. A telescope is not required to see this. It looks great in binoculars, and in a rural area on a cloudless night you can see it with the naked eye as a smudge of light. Place Mirach at the bottom of your binocular view and perhaps raise it a bit to see a slightly dimmer star in the upper line of Andromeda. Continue up about the same distance to another star and find the fuzzy expanse of the Andromeda Galaxy nearby. A small telescope will show two other galaxies, M32 and M110, in the same field of view. M31 is 2.5 million light years distant and heading our way. We will have a spectacular starry sky in four billion years, so keep breathing.
This Week in the Solar System
Saturday’s sunrise is at 6:35 and sunset will occur at 8:17, giving 13 hours, 42 minutes of daylight. Next Saturday the Sun will rise at 6:43 and set at 8:04, giving 13 hours, 21 minutes of daylight.
The new Moon occurs this Saturday, providing dark skies for the Fundy Star Party. Its crescent is between Mars and Spica in Tuesday evening twilight and below Spica the following evening. Around 5:30 am this weekend Jupiter and Mercury stretch across 25 degrees of the eastern sky with Venus between them, and by next weekend that stretches to over 30 degrees with Venus midway. Although Mercury is moving sunward it is also getting brighter. Uranus will be a binocular field below the Pleiades high in the southeast at that time. Saturn rises by 9 pm next weekend with Neptune less than half a binocular field above it. Orange Mars can be seen low in the west with binoculars around 9 pm, and if you can pick it out you have a good start toward completing an all-planet night.
The RASC NB star party at Fundy National Park takes place this Friday and Saturday, August 22-23. See the rascnb website for details. There will be public observing at Dutch Point Park in Hampton on the evening of August 29.