About once a year, Earth passes between the Sun and Neptune. This event is called an opposition because Neptune is on the opposite side of Earth from the Sun, rising around sunset and setting around sunrise. Earth is closer to Neptune at opposition than at other times of the year, so the weeks around opposition are the best time to view the distant planet. This year, Neptune will reach opposition on September 16.
Jupiter will reach opposition on September 26, just ten days after the opposition of Neptune. Like Neptune, Jupiter will appear slightly larger and brighter at opposition than it does throughout the rest of the year. Unlike Neptune, Jupiter is close enough to Earth that telescopes easily reveal several of its moons and a fair amount of detail on its surface.
On the night of October 11–12, the Moon will have a close encounter with Uranus. From eastern North America, the Moon will pass within 0.25° of Uranus in the wee hours of October 12. From the viewpoint of the western states and provinces, as well as the upper Midwest, the Moon will occult, or pass in front of, Uranus. The occultation will occur around midnight local time in the upper Midwest and before midnight in the western part of the continent.
The Orionid meteor shower will peak on October 21. This shower is a steady performer, producing maximum rates of around 20 meteors per hour. The Orionids have a broad peak, with near-peak rates visible for several nights around the peak night. A few meteors will be visible in the evening hours, but like most meteor showers, the highest rates will occur in the early morning.
A partial solar eclipse will take place on October 25. This eclipse will be visible from nearly all of Europe, along with northeastern Africa and western Asia. The Sun will be most obscured in central Russia, where it will be 82 percent eclipsed.
In Our Skies, September 2023: Planet Oppositions
