Sun rises at 5:58am
Sun sets at 6:27pm
Moon phase: second quarter, waxing to full
Moon sets at 3:16am, Saturday
Moon rises at 4:44pm, Sunday
This weekend we are blessed with an almost full moon; it will be truly full on Tuesday night. Look to the eastern sky after sunset. This will be the third and final full moon of the summer season in the Northern Hemisphere. And in the Southern Hemisphere, where it’s the opposite season, this September full moon counts as the third and final full moon of winter. Ah, symmetry!
Frequently, the September full moon is named the Harvest Moon, because the September full moon is – more often than not – the closest full moon to the autumn equinox. But in 2017, the October full moon actually occurs closer to the autumn equinox, so it’s this year’s Harvest Moon. When the September full moon is not the Harvest Moon, we commonly call it the Corn Moon.
When you’ve had your fill of the moon, turn your back on her and look westward. That brilliant “star” you see is actually Jupiter. Close by to our solar system’s largest planet, from our perspective, will be a couple of brilliant true stars: Spica (in Virgo), just below Jupiter, and Arcturus (in Bootes) above and to the right.
To the left or south of the Spica-Jupiter pair, about the same altitude as Arcturus, you can find Antares in the constellation Scorpius. Just above Arcturus and to the left is Saturn. Saturn, encircled by lovely rings of ice and rock, also has many moons. These have been visited by the spacecrafts Voyager 1 and 2, and more recently the Cassini Probe. Cassini is there still, sending us photos and data about the moons, the rings and Saturn herself. NASA just announced they will send Cassini into the atmosphere of Saturn where she will burn up, as her power source is dying and they don’t want her to become space junk. The Voyager probes, on the other hand, flew past Jupiter, Saturn and Neptune, and have left the Solar System, yet they still continue to send signals back, tiny postcards from humanity’s most distant traveller.
Our friend Orion, the Hunter, is back. Orion is often the only constellation non-stargazers know, because the three stars in a row (his belt) are so easy to spot. The constellation of Orion graces the predawn sky every year in late July. By early September, Orion is rising in the wee hours and is well up in the southeast an hour before dawn. Orion will soon be up by midnight, then by 10:00pm… and by December, you’ll find it rising in early evening.
There’s nothing unusual about Orion’s shift from the predawn to the evening sky. This constellation is simply doing what all the stars do throughout the year – shifting westward. This is caused by Earth’s orbit around the sun. As we orbit the sun, our night sky points toward an ever-changing panorama of the Milky Way galaxy. It’s our orbit around the sun that causes all the stars to rise about four minutes earlier each night.
You can use Orion’s Belt to find Sirius in the constellation Canis Major, the Big Dog. Sirius is the brightest true star in the night-time sky. The familiar three-star belt points you directly to Sirius. Imagine a line extending from the belt’s three stars. Follow it to a very bright star, and that is Sirius. Canis Major rises above the eastern horizon just after Orion does, about 2:45am.
Thank you for keeping up with the Night Sky articles. If you are out later on in the week, each star rises about four minutes earlier each day than written here, and the moon rises 50 minutes later. Night Sky is researched and compiled by Lisa Davis-Burnett. Earthsky.org is a key resource for information and images. Questions or comments? Email [email protected]