Eclipses, planetary conjunctions, meteor showers, lunar occultations: 2017 abounds with astronomical events! Here’s an overview.
Eclipses and occultations
Four eclipses, both solar and lunar, will be visible from different parts of the Earth this year; two of them will only be partially visible from Quebec. A penumbral lunar eclipse is set to occur on the evening of February 10, though it will be barely noticeable: At its maximum, around 7:43 p.m. EST, a slight darkening of the northern lunar surface should be visible to the naked eye, attenuating the full moon’s otherwise bright glare. Eclipses of this sort are usually easier to see in photographs: try taking some pictures with a good telephoto lens or through a small telescope.
The astronomical event of the year will no doubt be the total solar eclipse of August 21. The narrow band of totality will cross the United States, west to east, from Oregon to South Carolina and will be accessible by road to almost everyone in North America. Those who venture into this zone will experience one of the most extraordinary phenomena nature has to offer. But be prepared for lots of travellers and traffic that day: the challenge will be worth it… seeing a total solar eclipse is unforgettable! Outside the path of totality, the eclipse will be partial in varying degrees, and less impressive. From southwest Quebec, up to 60% of the Sun’s surface will be hidden by the Moon: It should serve as a dress rehearsal for the April 8, 2024 solar eclipse which will be total, seen from the southern half of the Island of Montreal, Montérégie and Estrie.
A different kind of eclipse, known as a lunar occultation, occurs when the Moon passes in front of planets or distant stars. For example, a series of occultations of Aldebaran, the brightest star in Taurus, began in January 2015 and will end in September 2018. The next two occultations of Aldebaran, visible from southern Quebec, will take place on the evenings of November 5 and December 30, 2017. Regulus, the bright star representing the heart of Leo, will also be occulted early on the morning of October 15. Meanwhile, during the night of January 17 to 18, the double star, Porrima (gamma Virginis), will be hidden by a waning gibbous moon: a small telescope will reveal the disappearance of both stars, around 00:19 a.m.; the duo will reappear on the opposite limb of the Moon less than an hour later, at about 1:17. The exact moment depends on one’s geographic location; it’s best to be prepared, eye to eyepiece, a few minutes ahead of time. Porrima will be occulted again on the evening of June 30, this time by the first quarter moon.
Meteors are visible all year long at any time of the night. But annual meteor showers significantly increase one’s chances of seeing shooting stars, which occur when the Earth passes through clouds of comet dust intersecting its orbit. That being said, this won’t be a good year for the mid-August Perseids, since the Moon’s glare will interfere with observations. However, the annual Quadrantids on the night of January 2 to 3, the Lyrids around April 22, and the Orionids around October 21 will all take place under favourable conditions. As for the Geminids, which reach their peak during the night of December 13 to 14, a “perfect storm” is brewing; astronomical circumstances will be exceptional… all we need hope for is a perfectly clear sky.
Regarding the planets
Mercury, the smallest planet and closest to the Sun, never wanders far from the glare of our daytime star; its periods of visibility alternate between dawn and dusk, and are brief. However, the tiny planet offers an excellent apparition in the morning sky, starting around the second week of January; look for it above the southeast horizon about 45 minutes before sunrise. Mercury’s best evening apparition will occur from mid-March to the first week of April, when it will shine above the west-northwest horizon 30 to 45 minutes after sunset. Your best chance to spot the furtive planet is at the beginning of this period, when Venus will shine nearby. Another excellent apparition, in the morning sky, takes place from September 8 to 28, with Mercury above the eastern horizon 30 minutes before sunrise; observing conditions will be optimal around mid-September.
Dazzling Venus plays a “starring” role in 2017. It starts the year as the Evening Star, shining high in the southwest at the beginning of twilight until four hours after sunset. On January 1, 2 and 3, follow the motion of the crescent moon past Venus and Mars, which shines a bit higher and to the left. Unlike Mars, Venus plunges back toward the Sun and moves into the morning sky where it will remain until December.
Mars won’t be at opposition this year; the next one will only take place in July 2018. As such, the Red Planet is too far and too small for telescopes to reveal any detail… so it is better left to the naked eye. Mars shines near Venus in the evening sky at the beginning of the year, and again in the morning sky this fall, after a summer passage behind the Sun.
Jupiter begins the year in Virgo, just a few degrees from the bright star Spica. In January, the brilliant planet rises in the east a bit after midnight and culminates in the south at the first light of dawn: Early on the morning of January 19, the last quarter moon will shine less than 3 degrees to the left of Jupiter. The giant planet will be at opposition on April 7, marking its prime observation period which will last until September. Jupiter will then disappear in the Sun’s glare for a few weeks and will return in the dawn sky as the year ends. On the morning of November 13, Venus and Jupiter will be scarcely one quarter of a degree apart, providing the year’s most spectacular conjunction.
Saturn moves slowly among the constellations because it takes nearly thirty years to orbit the Sun. This year, the planet continues to occupy the lowest part of the ecliptic, straddling the border of Ophiuchus and Sagittarius: As a result it never appears very high in the skies of Quebec, which hinders observation of its rings. However, since they are tilted to their maximum toward Earth, every opportunity should be taken to observe them! Until the beginning of May, Saturn will only be visible during the latter part of the night; but it arrives at opposition on June 15 and will be visible all evening throughout the summer until fall. On January 24, at the end of the night and at dawn, a thin lunar crescent will shine just 3 degrees to Saturn’s upper left; look for them in the southeast, an hour-and-a-half before sunrise.
Have a great 2017 and… Clear skies!