This Week’s Sky at a Glance, 2025 Sept 13 – Sept 20
This Week’s Sky at a Glance, 2025 Sept 13 – Sept 20
Autumn arrives next weekend and dedicated stargazers are happy to have the longer observing time afforded by earlier sunsets. The summer constellations appear reluctant to move on, however; emerging from twilight in nearly the same place each night because the earlier darkness masks that they rise four minutes sooner each day. But move on they do, and by mid-evening the two groups of autumn constellations lord over us.
Perseus sits below W-shaped Cassiopeia in the northeast these evenings. Cepheus is a house-shaped constellation north of Cassiopeia, and Andromeda lies with her feet below Cassiopeia and her head sharing a star with Pegasus. The asterism called the Great Square of Pegasus rises as a large diamond, a harbinger of the baseball post season. These constellations relate to a classic tale in Greek mythology, as does Cetus, playing the role of a ferocious sea monster. Cetus is actually a whale, and this segues to the second group – the water constellations.
To the southeast in evening twilight is the chevron-shaped Capricornus the sea goat. Above and left is the source of all this water; Aquarius, the water bearing servant of the Olympian gods. Below is the southern fish, Piscis Austrinus with its bright star Fomalhaut. Further east we have Pisces the fishes, the current home of Saturn, with Cetus swimming below them, and well above Capricornus we see Delphinus the dolphin leaping out of the sea.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 6:55 and sunset will occur at 7:33, giving 12 hours, 38 minutes of daylight (7:00 and 7:38 in Saint John). Next Saturday the Sun will rise at 7:04 and set at 7:20, giving 12 hours, 16 minutes of daylight (7:09 and 7:25 in Saint John).
The Moon is at third quarter this Sunday, near Jupiter among the stars of Gemini on Tuesday, and it teams up with Venus and Regulus Friday. Mars is within a binocular view above Spica this weekend, a challenging observation, setting an hour after sunset. On Friday morning Venus sits just above Regulus and just below the slim crescent Moon, with all three fitting within the view of most binoculars. Saturn rises soon after sunset as it approaches opposition next weekend. Mercury is at superior conjunction this Saturday.
The fall star party at Kouchibouguac National Park takes place this Friday and Saturday, See the RASC NB website for details. Tune in to the Sunday Night Astronomy Show at 8 pm on the YouTube channel and Facebook page of Astronomy by the Bay.