12 Astronomical Events in September 2024: What We’ll See in Autumn Sky?

As summer fades into the rearview mirror, there’s no need to feel downhearted. This year, September brings a wealth of celestial wonders that promise to delight stargazers. The nights grow longer and cooler, reducing atmospheric turbulence and enhancing visibility. Plus, the potential for auroras in the Northern Hemisphere adds an extra layer of excitement. So, find a dark spot away from city lights and prepare to be mesmerized by the cosmos. With so much on offer, there’s every reason to celebrate the arrival of fall!

Stargazing in the UK: Key Features

September offers us a unique blend of celestial events and viewing conditions. But what can UK stargazers expect? What sets the UK apart from other parts of the world is its northern latitude, which affects the visibility and timing of these events. For instance, the partial lunar eclipse will be more visible from the UK than from locations closer to the equator. The longer autumn nights in the UK provide extended viewing windows compared to more southern locations. Additionally, the UK’s position allows for potential sightings of the Aurora Borealis, especially in northern regions, as the aurora season begins. So, let’s see what you can see in the sky this month.

1 September: Conjunction of the Moon and Mercury

Firstly, let us explain what planetary conjunction is in simple words. It occurs when two or more planets, or a planet and another celestial object (such as the Moon or a star), appear to be near each other in the sky as seen from Earth.

On the 1st of September, you’ll have a chance to observe a conjunction of the Moon and Mercury at approximately 4:17 AM EDT, with Mercury positioned about 5 degrees below the crescent Moon. As a rule, Mercury, the smallest planet in our solar system can be challenging to spot due to its proximity to the Sun. But not this time! To enhance your viewing experience, consider finding a location with a clear view of the eastern horizon just before dawn. Binoculars may help spot Mercury, especially if you’re in an area with light pollution.

Curious about what the conjunction looks like in the sky? Check it out here.

3 September: New Moon 

Set the alarm for 01:55 GMT. During this phase, the Moon is positioned directly between the Earth and the Sun, leaving its illuminated side facing away from us, resulting in a completely dark sky. Since the New Moon won’t be visible, it’s also a perfect time for stargazing, as the darker skies enhance visibility for observing other celestial objects.

5 September: Mercury at Greatest Western Elongation

It’s a key astronomical event for observing the elusive Mercury. Elongation refers to the angular separation between a planet and the Sun as seen from Earth. For inner planets like Mercury and Venus, the greatest elongation marks the maximum apparent distance from the Sun in our sky. This occurs at approximately 1:59 AM GMT, when Mercury will shine brightly at a magnitude of -0.4, making it easier to spot against the dawn backdrop.

During this western elongation, Mercury will be positioned about 27 degrees away from the Sun in the morning sky. This separation provides a rare opportunity to observe Mercury. To witness it, look towards the eastern horizon 30 minutes before sunrise. Remember to use binoculars for a closer look, but ensure the Sun is well below the horizon to avoid any risk to your eyesight. 

8 September: Saturn at Opposition

Saturn will reach opposition at 4:27 AM GMT (12:27 AM EDT), making it one of the best times to observe the Ringed Planet. During opposition, Saturn will be positioned directly opposite the Sun in the sky, allowing it to shine at its brightest with a magnitude of 0.6. This alignment means that as the Sun sets in the west, Saturn will rise in the east, becoming visible throughout the night. To catch a glimpse of this celestial event, look for Saturn in the constellation Aquarius, where it will be easily identifiable as a bright yellowish dot. For a closer look at its stunning rings, use a telescope with at least a 4-inch aperture.

Additionally, around the time of opposition, observers may notice the Seeliger Effect, which causes Saturn’s rings to appear unusually bright due to the sunlight reflecting off the ring particles without casting shadows. This is a perfect opportunity for stargazers and astrophotographers alike, so make sure to find a dark spot away from city lights and enjoy the beauty of Saturn in all its glory!

9-10 September: Epsilon Perseids Meteor Shower

As for meteor showers, September is relatively quiet compared to other months. However, you can still enjoy the subtle beauty of the Epsilon Perseids, which typically peak around 9-10 September. This meteor shower is known for producing a few meteors per hour under optimal dark-sky conditions. While not as prolific as the more famous meteor showers, it still gives us an opportunity to catch some shooting stars.

17 September: Moon near Saturn & Lunar Occultation

On this day, the Moon will make a close approach to Saturn, culminating in a lunar occultation visible from select regions. It will be visible from parts of the western United States, western Canada, northwestern Mexico, and Australia, among other locations. For those outside the occultation zone, a close conjunction between the Moon and Saturn will still be observable.

To witness this spectacular event, look towards the eastern sky after sunset. Saturn will appear as a bright, yellowish “star” near the nearly full Moon. For the best view, use binoculars or a small telescope, which will allow you to see Saturn’s iconic rings. The exact timing of the occultation varies by location, so check local astronomical resources for precise times.

Even if you’re not in the path of the occultation, this close pairing of the Moon and Saturn offers a fantastic photo opportunity. Try capturing the scene with a long exposure to bring out the details of both celestial bodies.

18 September: Full Moon, Supermoon & Partial Lunar Eclipse

What a day! Stargazers are in for a celestial treat as a Full Moon, Supermoon, and Partial Lunar Eclipse coincide in a rare astronomical event. The Full Moon will occur at 2:34 AM BST (British Summer Time), offering a bright spectacle in the night sky. This Full Moon is also a Supermoon, appearing up to 14% larger and 30% brighter than a typical Full Moon due to its closer proximity to Earth.

RELATED: September Full Moon 2024: What Does The Harvest Moon Bode For Us?

The highlight of the night, however, will be the Partial Lunar Eclipse. For UK observers, the eclipse will begin at 1:41 AM BST as the Moon enters Earth’s penumbra. The partial phase, when the Moon starts to visibly darken, begins at 3:13 AM BST. The maximum eclipse, with about 3.5% of the Moon’s surface covered by Earth’s umbral shadow, occurs at 3:44 AM BST. The eclipse will end at 5:47 AM BST, just before moonset in most UK locations.

The early hours of the morning will provide the darkest skies for observation. Binoculars or a small telescope can enhance the view, especially for observing the subtle changes during the penumbral phase. 

21 September: Neptune at Opposition

Like Saturn, Neptune will be at its closest approach to Earth and fully illuminated by the Sun. Although a telescope is needed to see this distant planet, it will be brighter than at any other time of the year. Even at opposition, Neptune will appear as a small, star-like point of light, so a telescope will provide the best view of this fascinating planet. 

22 September: September Equinox

It’s the official start of autumn in the Northern Hemisphere and spring in the Southern Hemisphere! The September Equinox will occur at 12:44 PM UTC, marking a significant turning point in the Earth’s orbit.

RELATED: Autumn Equinox 2024: What & When Is The First Day Of Fall?

During the equinox, the Sun crosses the celestial equator, resulting in nearly equal lengths of day and night across the globe. It means that as the Sun rises due east and sets due west, you can experience a perfect balance of light and darkness. 

23 September: Moon near Jupiter 

Observe the Moon in close proximity to Jupiter. The two objects will appear near each other in the night sky, making it an excellent time for stargazing. The Moon will pass close to Jupiter, providing a beautiful sight in the night sky and an excellent opportunity for photography.

To catch this event, look towards the southeastern horizon after sunset; the best viewing time will be around 8:00 PM BST, when both the Moon and Jupiter will be high enough in the sky for optimal visibility. 

25 September: Moon near Mars 

In two days, the Moon will also pass near Mars, offering another chance to see these two celestial bodies in close proximity. The best viewing time will be around 8:00 PM BST, when the sky is dark enough to appreciate their brightness. Binoculars or a small telescope can enhance your experience, allowing you to see Mars more clearly and perhaps catch a glimpse of its surface features. 

27 September: Tsuchinshan-ATLAS Comet

On this day, comet C/2023 A3 (Tsuchinshan-ATLAS) is expected to pass perihelion, meaning it will be at its closest point to the Sun. During September, it will move from a magnitude of 7 to 3, making it increasingly visible in the morning sky of the Southern Hemisphere. By the end of the month, it will start appearing in the morning sky in the Northern Hemisphere, offering a short observation window to capture its tail.