Here are some details on the Moon’s different phases, close approaches of planets with the Moon or the Sun, and other astronomical events in October.
October 1: Venus at perihelion. Venus’s revolution around the Sun, which lasts 225 days, will take it to its closest from to the Sun – its perihelion – a distance of 0.72 astronomical unit (AU), or 107,710,466 km.
October 4: The Moon at aphelion (91%), its greatest distance from the Sun – 152,457,150 km – at 10:10 a.m. Eastern Daylight Time (EDT).
October 5: Conjunction – Close approach: the Moon (98%) and Saturn (mag: +0.64). Visible starting at moonrise in the East (as the Sun sets) and throughout the night, the two heavenly bodies following in each other’s path take a beautiful walk from east to west, between sunset and sunup. A breathtaking spectacle. Saturn is located just below (to the south) of the Moon.
October 6: Full Moon (100%) at 11:47 p.m. EDT.
October 8: The Moon (97%) at perigee. It will be closest to the Earth (356,500 km) at 8:38 a.m. EDT.
October 8: Maximum Draconid meteor shower at 3:12 p.m. EDT. Probably the largest Draconid shower of the decade, and by far the most important from the standpoint of space missions. But this year it will barely be visible to the naked eye (visible mostly on radar). The presence of the full Moon two days before won’t help you see this phenomenon, which will not be very bright.
October 9: Conjunction – Close approach: the Moon (88%) and the open cluster M45 (the Pleiades). It’s young-star open cluster M45’s turn to join the walk beside the Moon. Visible from sunrise to sunset the night of October 9-10, M45 will be just below, to the left of the Moon.
October 10: Mercury at aphelion. The revolution of Mercury around the Sun, which lasts 88 days, will take it to its furthest point from the Sun – its aphelion: a distance of 0.47 AU, or 70,310,999 km.
October 13: Last Quarter Moon (50%) at 2:13 p.m. EDT.
October 13: Conjunction - Close approach: the Moon (45%) and Jupiter (mag: -2.2). After Saturn and M45, it’s Jupiter’s turn to dance with the Moon. Located to the Moon’s right when it rises in the east starting at 23:45 p.m. EDT the night of October13, Jupiter will follow the Moon until sunrise on October14. A spectacular duo you won’t want to miss.
October 19: Conjunction - Close approach: the Moon (4 %) and Venus (mag: -3.91). Venus won’t be left behind in this celestial ballet. After Saturn, M45 and Jupiter, the duo of Venus and a very thin crescent Moon will dazzle us in the early hours of October19. Visible to the east beginning at 5:45 a.m. on the 19th, this duo will be the showstoppers of planetary encounters with the Moon this month, just as it was last month.
October 21: New Moon (0%) at 08:26 a.m. EDT.
October 21: Conjunction - Close approach of Mercury (mag: -0.17) and Mars (mag: +1.45). Just after sunset, in an easterly direction, with a beautiful clear horizon, it will be possible to see Mercury and Mars (slightly to its right and higher). But a difficult show to take it in, being situated very low on the horizon. You’ll need to wait for the Sun to set to see it well.
October 21: Maximum Orionid meteor shower at 8:21 a.m. EDT. The shower will be active from October 2 to November 7, reaching its peak of meteor activity around October 21. Seen from Montréal, it will only be visible starting at 10:02 each night, when its radiant climbs above the eastern horizon. It will then remain active until dawn, around 6:45 a.m.. This is quite an active shower, and an opportunity to see big, very fast bolides. Be on the lookout!
October 23: The Moon at its apogee (5 %) – its farthest distance from the Earth (406,700 km) – at 7:30 p.m. EDT.
October 23: Conjunction - Close approach of the Moon (5 %) and Mercury (mag: -0.17), just after sunset. A very thin crescent Moon will allow us to find Mercury to its right, and Mars to the right of Mercury. A difficult trio to see, because very low on the horizon.
October 24: The Moon at perihelion (10%) – its closest distance from the Sun (149,597,871 km) – at 7:14 a.m. EDT.
October 29: First Quarter Moon (50%) at 12:21 p.m. EDT.
October 29: Mercury at its greatest eastward elongation (mag: - 0.12 and 62% phase), i.e., its greatest separation from the Sun (5 degrees altitude) at sunrise.
All month: Look for Neptune! During the entire month of October, Neptune will be located just above (to the north of) Saturn. Impossible to see with the naked eye, you’ll be able to spot it with a small telescope or binoculars.
