October 2022 offers a beautiful transition sky that will bring noteworthy astronomical phenomena in the coming months.
Take advantage of the long but still-mild nights to enjoy the summer constellations that will soon leave us. The Summer Triangle—formed by Deneb, Vega and Altair, the brightest stars in the northern constellations Cygnus, Lyra and Aquila—sets increasingly earlier, but Andromeda dominates the sky at the zenith around midnight while Orion begins to appear in the east at the same time.
Planets and more planets
Amateur astronomers and astrophotographers are in for a treat as several planetary gems still grace the sky this October.
Mercury makes an excellent appearance in the morning sky from September 30 to October 27. Look for the tiny planet above the eastern horizon 45 minutes before sunrise. It reaches its highest elevation around October 8, a dozen or so degrees above the horizon. After October 24, it will be too low to be easily spotted.
The Mars opposition will only take place on December 7, but the Red Planet has already drawn very close to Earth in the last few weeks. The viewing conditions will be very good, given the planet’s apparent diameter of greater than 15 arc seconds (from October 30 to December 29) and the fact that it culminates at about 69 degrees above the southern horizon. The Red Planet shines in Taurus, which is clearly visible above the east-northeastern horizon, around 11 p.m. in early October and 9 p.m. by month’s end. During the night of October 13 to 14, the waning gibbous Moon glides between the Pleiades open star cluster and Mars, with the Hyades open cluster directly below it at around 10 p.m.
Jupiter was at opposition on September 26. The giant planet has therefore officially re-entered the evening sky and culminates increasingly earlier each day. October is the perfect time to observe Jupiter through a small telescope. Its disc currently has an apparent diameter of nearly 50 arc seconds: Admire the cloud bands in its atmosphere, or even try to locate the Great Red Spot. On October 8 at twilight, the nearly full, waxing gibbous Moon shines below Jupiter, low on the eastern horizon; the two celestial bodies culminate around midnight, but the gap between them widens over the course of the evening.
Saturn was also at opposition on August 14, with its rings tilted about 14 degrees to our line of sight. In early fall, Saturn culminates increasingly earlier in the evening; by late October, the ringed planet even sets before midnight. This is another great opportunity to observe the most beautiful of the planets, especially since night falls very early now. On October 5 at twilight, the waxing gibbous Moon will appear to the lower left of Saturn in the southeast; the two celestial bodies will culminate at about 9:30 p.m., but the gap between them widens throughout the evening and night.
Shooting stars galore!
The Orionids peak on October 21. Although considered one of the least showy of the annual meteor showers, the Orionids are long-lasting and have a very broad maximum. The level of activity is variable from year to year, possibly on a 12-year cycle that could reach its most intense phase during the 2020-2022 period. So, if you want to catch the show, look skyward around October 21 and until the New Moon on the 25th. This shower, associated with Halley’s Comet, produces rather faint but extremely fast meteors (67 km/s), which often explode in terminal bursts that sometimes leave persistent trains behind them. The Orionid radiant rises around 10 p.m., reaches a reasonable height after midnight and culminates at dawn.
A solar eclipse
And lastly, the New Moon of October 25 will also be accompanied by a partial eclipse of the Sun, which won’t be visible from North America. However, it will be visible to varying degrees in western, northern and central Europe, western Russia, the Middle East as far as India, and northeast Africa. It serves as a reminder that one year from now, on October 14, 2023, an annular eclipse will be visible in North America, and that six months later, on April 8, 2024, a total solar eclipse will cross southern Quebec. You won’t want to miss these ones!