What's Up - October 2023

What's Up for October? Some great Moon-and-planet pairings, a mission to a metal-rich world, and a partial eclipse of the Sun.

On October 2nd, the Moon rises a couple of hours after sunset, appearing super close to the Pleiades star cluster. Look for them low in the east after around 10pm. They travel across the sky together that night, leaving another opportunity to see them the following morning. In the predawn sky on October 3rd, the Moon appears a couple of finger widths apart from the Pleiades, having moved a bit in its orbit around Earth during the night. Look for them high in the southwest, flanked by Jupiter and the bright, red giant star Aldebaran in Taurus.

On October 10th, look for Venus in the east before sunrise, accompanied by a slim crescent Moon. And in between them, the bright heart of Leo the lion, bluiush-white star Regulus.

On October 23rd, look toward the south an hour or two after sunset to find the Moon, about 70% illuminated, hanging just beneath the planet Saturn. Their close proximity in the sky will make for some easy telescope viewing of these two skywatching favorites. The following evening, the Moon will still be nearby, having moved to the east of Saturn.

The full moon on October 28th rises together with planet Jupiter. These are two of the brightest objects in the sky, and seeing them so close should make for quite an impressive sight.

When you gaze up at Venus, Mars, Mercury (or even down at Earth beneath your feet), do you ever wonder how these planets formed out of stardust? That's how planetary scientists think, too. And this month, NASA's launching a spacecraft to seek new insights into how the "terrestrial" planets developed. NASA's Psyche spacecraft is planned to launch in October on its multi-year journey to an asteroid of the same name. It's the first mission to a metal-rich asteroid, which could be part of the interior of a planetesimal – a building block of a rocky planet.

Asteroid Psyche could also turn out to be a different kind of iron-rich object that's not been seen before. Whatever its story turns out to be, it's hoped the mission might show us how Earth’s core and the cores of the other terrestrial planets came to be.

On October 14th, skywatchers in the Americas will have an opportunity to see a special type of solar eclipse called an annular eclipse. Along a path about 125 miles wide, the Sun will appear as a narrow ring of light, which is often called a "ring of fire." This narrow circle shape is also known as an annulus, giving this type of eclipse its name.

Solar eclipses happen when the Moon comes between Earth and the Sun, and covers at least part of the Sun in the sky. When the Moon covers the Sun completely, we get to

observe a total eclipse. But sometimes the Moon is a bit farther away in its orbit when an eclipse happens, making it look a little smaller in the sky, and just a bit too small to completely cover the Sun. When that happens, it enables us to see an annular eclipse.

The path of this partial eclipse sweeps across the Americas, beginning in Southern Canada and crossing the Western U.S., before moving across Central and South America. Outside the annular eclipse path, those within the viewing zone will still see a partial eclipse. The maximum amount of the Sun that will be covered by the Moon depends on your location.

Now, eclipse fans won't have to wait long for more excitement. Next April, a total solar eclipse will sweep across the U.S. Check out NASA's eclipse resources online for info about both eclipses, where they'll be visible, and tips for safe viewing.

Here are the phases of the Moon for October. Stay up to date with all of NASA's missions to explore the solar system and beyond at nasa.gov. I'm Preston Dyches from NASA's Jet Propulsion Laboratory, and that's What's Up for this month.