There are a lot of great things to watch in the October sky, including Sirius, the brightest star, two meteor showers, planetary lineups, and a full Moon! Autumn mornings are also a good time of year to spot the Zodiacal Light, or “False Dawn.”
All events are Eastern Daylight Time and as seen from the Northern Hemisphere:
October 5 — Around 5 a.m. local daylight time, look 10° (roughly equal to the width of your clenched fist held at arm’s length) above the eastern horizon to see planets Venus and Mars pass outstandingly close to each other. In the Eastern U.S. they are separated 0.27° — about half the apparent width of the Moon. The Western U.S. sees them even closer: 0.22°. Casual skywatchers can easily miss this pairing, however, since Mars is 191 times fainter! To make Mars easier to see, try using binoculars. Mars hovers to the lower right of Venus. By Halloween it is 16° above and to the right of Venus.
October 5 —Full Harvest Moon, astronomically full at 2:40 p.m. In this phase, the entire disc of the Moon is fully illuminated by direct sunlight. Though the Moon is only technically in this phase for a few seconds, it is considered “full” for the entire day of the event and appears full for three days. This month’s Moon is the Harvest Moon because it is the full Moon closest to the Autumnal Equinox. Usually the title of Harvest Moon goes to the September full Moon. But from 1970 to 2050 the Harvest Moon falls in October no fewer than 18 times. And 2017 is one of those years.
October 7 & 8 — The annual Draconid meteor shower, also sometimes called the Giacobinids, will peak. Usually a moderate meteor shower originating near the constellation Draco, the Draconid meteors are created by dust left behind by the periodic comet Giacobini—Zinner. This shower is best viewed in the evening hours. Watch for the Draconid meteors first thing at nightfall – or before the bright Moon rises.
October 9 — The waning gibbous Moon is at perigee, meaning it’s at its closest point to Earth for the month.
October 12 — Last Quarter Moon, 8:25 a.m. In this phase, the Moon looks like a half-Moon in the sky. One-half of the Moon is illuminated by direct sunlight while the illuminated part is decreasing, on its way to the New Moon (invisible) phase.
October 12 – Can you spot Capella, our 6th brightest star? It’s the one that’s doing a lot of colorful twinkling. Look low in the northeastern sky on these autumn evenings — locate the Big Dipper asterism, then follow the cup straight across to the east, to Capella.
October 15 — The occultation of Regulus by the Moon. Before dawn, most of the contiguous U.S. (except the Pacific Northwest and parts of the Northern Plains) and Southeast Canada, and parts of the Maritime Provinces, will be able to see the Moon cover the bright bluish star, Regulus, known as the Heart of the Lion in Leo. See if you’re in the zone of visibility.
October 16 – Set your alarms! Look to the east about an hour before sunrise to spot the tiny crescent Moon above Venus and Mars.
October 19 — New Moon, 3:12 p.m. At this stage, the Moon is not illuminated by direct sunlight and is completely invisible to the naked eye.
October 21 & 22 — The Orionid Meteor shower peaks ! This shower is the cosmic dust from the most famous comet, Halley’s comet. The meteors appear to emanate from a point near the Orion-Gemini border in Orion’s upraised club, hence the name. This year should be very favorable for viewing as the moon is just past new phase so skies will be dark. View overhead from 1 to 2 a.m. local daylight time until dawn; you may see 20-25 meteors per hour!
October 22 – Look an hour after sunset to spot the crescent Moon, the planet Saturn, and the star Antares low in the southwest horizon.
October 23 & 24 — Look for Saturn near the waxing crescent Moon. It glimmers into view during twilight low in the southwest, followed a few minutes later by slightly dimmer star Antares, located about 13° to its lower right.
October 24 — The waxing crescent Moon will be at apogee, meaning its farthest point from Earth during the lunar month. An easy way to remember: (A)pogee = (A)way.
October 27 — First Quarter Moon, 6:22 p.m. In this phase, the Moon appears as a half Moon in the sky. One-half of the Moon is illuminated by direct sunlight while the illuminated part is waxing (increasing), heading toward the full Moon.
October 30 —High in the northern sky and nearly overhead at around 11 p.m. local daylight time is the zigzag row of bright stars that make up the constellation of Cassiopeia, the Queen. In fall, Cassiopeia hovers high above Polaris, the North Star, and her “M” shape is most recognizable. The Milky Way also runs straight through Cassiopeia. This star-rich region has long been considered a happy-hunting ground for skywatchers with binoculars and small telescopes scouting out many bright and easy-to-see star clusters.