Equatorial Sky Guide - September

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:20Welcome to the 365 Days of Astronomy. I'm Aviva, your host, and this is the Equatorial Sky Guide for September 2026. September brings us bright planets, a dark window for exploring the Milky Way, and a special encounter between the Moon and Venus. So let's see what's happening in the sky this month. Let's begin just after sunset. Venus continues to dominate the western sky as our brilliant evening star. You won't have much trouble finding it. Venus is by far the brightest planet in the evening sky. Just look to the west.

0:53During September, Venus can be found among the stars of Virgo. It reaches its greatest brilliance around September 18, but it also gradually moves lower toward the western horizon as the month progresses. Mercury joins the evening sky around the middle of September. Look for it very low in the west after sunset. It remains in Virgo throughout the month, and toward the end of September, Mercury passes close to Spica. Saturn is also becoming an excellent target for evening observers.

1:27The ringed planet rises in the evening and remains visible for most of the night. Even a small telescope can reveal Saturn's famous rings. Although in 2026, we are viewing those rings at a relatively narrow angle. After midnight, Mars joins the sky. The reddest planet rises in the early morning hours and remains visible until dawn. It begins September among the stars of Gemini, before moving into Cancer later in the month. Jupiter rises later, close to dawn.

1:59Early in September, the giant planet appears fairly low in the morning sky, but it becomes easier to observe as the month progresses. Farther away, Uranus and Neptune are also in the night sky, but you will need optical aid to find them. Neptune reaches oppositions on September 26. Around oppositions, the planet rises near sunset and remains visible throughout the night. But even at its best, Neptune is far too faint for the unaided eye. Through a telescope, look for a tiny bluish point among the stars of Pisces.

2:34The moon provides several useful sign spots this month. Before sunrise on September 7, look for the waning recent moon near reddish Mars. To morning leaders on September 9, for observers around Indonesia and nearby equatorial longitudes, the moon appears close to bright Jupiter before sunrise. After new moon on September 11, the action moves to the evening sky, and this brings us to the highlight of the month. On September 14, the young recent moon passes extremely close to Venus.

3:08From some parts of the world, the moon will actually pass directly in front of Venus. This is called a lunar occultation. The occultation is visible from a broad region covering parts of Asia, Africa, the Middle East, and Europe. Parts of Indonesia are also inside the visibility region. For observers in western Indonesia, this can become a beautiful early evening event. From Bandung, for example, Venus disappeared behind the moon at around 7.56 pm local time, although the pair search before Venus emerge again.

3:43If you are outside the occultation path, don't worry. The crescent moon and brilliant Venus will still make a beautiful close pairing in the sky. Just remember that occultation's visibility is extremely location-dependent, so check the circumstance for your observing sight. A few evenings later, on September 17, the moon moves close to Antares, the bright red star marking the heart of Scorpius. The two appear less than a degree apart, an easy and attractive pairing for the unaided eye.

4:15New moon occurs on September 11, making the middle of the month a particularly good time to escape city lights and explore the darkest sky. After evening twilight, look overhead for three bright stars, Vega, Altair, and Danep. Together, they form the famous Summer Triangle. From equatorial latitudes, this large stellar triangle stretches prominently across the evening sky and makes a useful starting point for navigating the stars.

4:45Turn toward the south and you'll find Scorpius and Sagittarius. Antares marks the heart of Scorpius, while the stars of Sagittarius point us toward the center of our Milky Way galaxy. From truly dark locations far away from artificial lights, the Milky Way appears as a faint luminous band crossing the sky. Binoculars reveal even more. Then star fields, clusters, and dark patches of interstellar dust scatter across the galactic plane. Later in the evening, look toward the southern sky for Fomalhaut, the brightest stars in Pisces Austrinus.

5:22Meanwhile, Pegasus begins climbing higher in the east. These bright stars can become your landmark as the September sky slowly changes through the night. There is one more important event this month. On September 23rd, at about 5 past midnight UT, the Sun crosses the celestial equator marking the September equinox. For the northern hemisphere, this marks the beginning of astronomical autumn, while south of the equator, it will be spring begins.

5:52But here, near the equator, the event has another interesting consequence. Around the equinox, the Sun rises almost exactly in the east and sets almost exactly in the west. For locations very close to the equator, the midday Sun can also pass very high overhead around this time of year. It is a nice reminder that the changing seasons are really a consequence of Earth's tilted axis as our planets travel around the Sun. And finally, if you want to do more than simply look at the stars, September is also a good month to measure your night sky.

6:28The Club at Night campaign runs from September 2nd to 11th. Observers in the southern hemisphere can use Sagittarius to estimate how much light pollution affects their local sky. And for observers in the northern hemisphere, they can use Cygnus constellation. The fewer stars visible, the brighter your night sky may be because of artificial light. So this September, watch Venus glowing after sunset. Follow Saturn through the evening. Look for Mars after midnight and Jupiter toward dawn.

7:01Explore the Milky Way during the dark nights around New Moon. And if you are in the right place, watch Venus briefly disappear behind the Moon. And remember, you don't need complicated equipment to start exploring the night sky. Sometimes, all you need is a clear sky, a dark place, and the curiosity to look up, and of course, your eyes. Thank you for listening. This is 365 Days of Astronomy. You are listening to the 365 Days of Astronomy podcast.

7:37Cool. The 365 Days of Astronomy podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drumm. Project management is by Aviva Yamani. And hosting is donated by LibSyn.com. This content is released under a Creative Commons attribution, non-commercial 4.0 international license.

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8:44With every new discovery from ground-based and space-based observatories and each milestone in space exploration, we come closer to understanding the cosmos and our place within it. Until next time, let the stars guide your curiosity.