The Night Sky This Month – September 2025
(Looking for last month’s ‘Night Sky’? Find it at this link…)
Wow, it’s a busy month in the heavens in September. Venus lights up the eastern sky in the morning as brightening Jupiter lies higher and further west. Mars plunges towards the southwestern horizon after sunset. And Saturn emerges into the evening sky as it reaches opposition this month (as does Neptune). Deep-sky observers enjoy longer nights to enjoy the Milky Way and all its celestial treasures. And the September equinox arrives to mark a change of seasons. Here’s what to see in the night sky this month.
1-2 September 2025. Venus lies about a degree south of the Beehive star cluster over the eastern horizon before sunrise. The planet is nearly 85% illuminated and shines at a brilliant magnitude -4.0. Take in the planet and cluster in binoculars and look for 4th-magnitude delta Cancri nearby.
6 Sept. Uranus reaches its first stationary point and begins retrograde motion for the next 22 weeks. The 6th-magnitude planet lies nearly 5o south-southeast of the Pleiades. Try to fit the planet and star cluster together in a pair of binoculars.
7 Sept. Full Moon, 18:09 UT (the full ‘Corn Moon’)
7 Sept. A total lunar eclipse is visible across western Australia, eastern Africa, and much of India and Asia. A partial lunar eclipse is visible over a wider area including all of Australia and New Zealand. Detailed timing of the event at this link.
8 Sept. Saturn lies 4o south of the Moon with Neptune in between the two. The latter planet requires binoculars or a telescope to see. Saturn is well-placed for telescopic observation for the next few months and reaches opposition later in September.
12 Sept. Grab your binoculars again and look low in the southwest after sunset to see Mars just 2o north of 1st-magnitude Spica. Look for the color contrast between ochre Mars and the star’s ice-white hue.
13 Sept. Mercury reaches superior conjunction with the Sun and remains unobservable for most of the month.
14 Sept. Last Quarter Moon, 10:33 UT
16 Sept. Look for Jupiter 5o south of the crescent Moon in the eastern early-morning sky. The planet is slowly moving closer to Earth and offers much to see in a small telescope.
17 Sept. A waning crescent Moon lies 2o north of the Beehive cluster in the eastern sky before sunrise.
19-30 Sept. Over the next two weeks, northern-hemisphere observers with very dark sky can see the zodiacal light in the east about 90-120 minutes before sunrise. This whitish wedge of light appears to thrust upward from the horizon towards the constellations Gemini and Cancer. The zodiacal light is simply sunlight reflected off tiny dust particles in the inner solar system.
19 Sept. Look eastward before sunrise to see a modestly spectacular event – Venus, Regulus, and a waning wafer-thin Moon in a line less than 2o long. Naked eye, binoculars, telescope – use whatever you have at hand to witness this beautiful celestial alignment.
21 Sept. New Moon, 19:54 UT
21 Sept. Saturn reaches opposition and rises in the east as the Sun sets in the west. The planet lies 8.55 AU from Earth tonight just southeast of the Circlet of Pisces. This marks its closest approach to Earth in 2025. The planet is slowly moving northwards and now lies about 2.9o south of the celestial equator, so it’s well positioned for all observers to get good views of its magnificent ring system. It’s worth the effort: Saturn is one of the most beautiful objects to observe in a telescope. At opposition, its disk spans about 19” and its rings about 45” and reaches a brightness of magnitude +0.6. The rings are tilted just 2o to our point of view this year which makes for a unique view of the southern side of the rings. Our Saturn Observing Guide will help you get a good view of this lovely celestial object and understand what to look for. Tonight, the planet lies in Pisces, but it moves westward in retrograde and enters Aquarius by month’s end. Saturn remains visible through the rest of the year.
21 Sept. A partial solar eclipse descends across New Zealand, the south Pacific, and parts of Antarctica. Detailed timing of the event here.
22 Sept. The September Equinox arrives at 18:19 UT marking the first day of autumn in the northern hemisphere and spring in the southern hemisphere.
23 Sept. Neptune reaches opposition near the ‘Circlet of Pisces’, about 2.6o northeast of Saturn. The planet itself, which lies today at a distance of 4.3 billion kilometers, shines at magnitude 7.8 and spans a diameter of just 2.4”. You can spot the planet in binoculars, but you need a telescope at about 150x or more to reveal its pale blue-green disk.
27 Sept. A waxing crescent Moon lies two to three degrees north of the red supergiant Antares in the southwestern.
29 Sept. First Quarter Moon, 23:54 UT