Here’s a quick look at what’s going on in the sky during the month of September 2017:
All events are Eastern Time and as seen from the Northern Hemisphere:
By early September, you’ll be able to spot Orion the Hunter rising in the early dawn hours!
September 4 — Neptune, the 8th planet from the Sun, will be the closest to Earth for the year. On the 5th, it reaches opposition,which means it’s most opposite the Sun for the year.
September 6 — Full Moon at 3:03 a.m. At this phase the visible Moon is fully illuminated by direct sunlight. But is it the full Harvest Moon or the full Corn Moon? While many might think the Harvest Moon is always in September, it’s really the full Moon nearest the autumnal equinox (September 22, this year). September’s full Moon is the third and final full Moon of the summer season, but in 2017, the October full Moon actually occurs closer to the autumn equinox, so October’s full Moon is this year’s Harvest Moon. When the September full moon is not the Harvest Moon, we call it the Corn or Barley Moon.
September 12 – Before dawn, try to spot the waning gibbous Moon and the bright star, Aldebaran, in constellation Taurus — If you live in Hawaii or the US West Coast you might be able to see the Moon occult Aldebaran before dawn.
September 12 – This week is a great time to view Mercury in the early morning hours. It rises 90 minutes before sunrise and it reaches its greatest morning elongation from the Sun (18o west) on September 12.
September 13 – Last Quarter Moon at 2:25 a.m. In this phase, the Moon appears as a half Moon. One-half of the Moon is illuminated by direct sunlight while the illuminated part is decreasing, heading toward the New Moon (invisible) phase. It’s called the “Last Quarter” Moon because this is the last quarter of the 29+ day lunar cycle. Note how it occurs approximately 7 days from the full Moon.
September 13 – The Last Quarter Moon (half Moon) is at perigee, its closest point to Earth in its orbit. This is the year’s farthest perigee of the year.
September 16 – Set your alarms 90 minutes before Sunrise to see a super close conjunction of Mercury and Mars low in the eastern horizon. The crescent Moon and Venus will be higher in the sky.
September 17th and 18th – Look to the east about 40 minutes before sunrise to see the tiny waning crescent Moon above Venus. But hurry, once the Sun rises, Venus will disappear!
September 21 – Look to the west about 1 hour after sunset to see the tiny waxing crescent moon and the planet Jupiter. But hurry! They’ll disappear beneath the horizon before it gets dark.
September 22 – Autumn begins at 4:02 p.m. with the Autumnal Equinox. The Sun crosses the Equator and darkness begins to win out over daylight. It also means the Sun will rise due east and set due west!
September 26 – Look to the southwest as soon as it gets dark to see the waxing crescent Moon pair up with Saturn. They’ll set beneath the horizon by mid-evening. Nightfall also is the best time to view Saturn’s rings through a telescope.
September 27 – First Quarter Moon, 10:54 a.m. In this phase, the Moon looks like a half-Moon — one-half of the Moon is illuminated by direct sunlight while the illuminated part is increasing, on its way to full. It’s called the “first Quarter” Moon because in this phase, the Moon is in its first quarter of the 29+ day lunar cycle.