Another year of skywatching is upon us, and there's a lot to look forward to in 2021!
Here are the 10 most noteworthy sky events. A close pairing-off between two bright planets, a total and nearly total eclipse of the moon, a great year for viewing the beloved Perseid meteors and a great autumn appearance for Venus are among the celestial highlights that will take place in the new year.
Of course, Space.com's Night Sky column will provide more extensive coverage of these events as they draw closer.
Jan. 3: The Quadrantid meteor shower
At present, the Quadrantid meteor shower is probably — along with the Geminids of December — the richest annual meteor display but one of the briefest; six hours before and after maximum, these blue meteors appear at only a quarter their highest rates. This year, the maximum of the shower is predicted to occur at 1500 hours GMT.
Unfortunately, the waning gibbous moon will interfere with observations. Under more favorable conditions you might count several dozen meteors per hour. The Quadrantids' radiant (from where the meteors appear to fan out) is located halfway between the head of Draco and the end of the Big Dipper's handle, high in the northeast sky during the early morning.
March 5: Jupiter and Mercury meet
Jupiter and Mercury are barely above the east-southeast horizon during dawn, but this morning they're engaged in a very close conjunction, separated by just 0.35 degrees. Mercury (magnitude +0.1) will sit just to the upper left of much brighter Jupiter (magnitude -2.0); the solar system's biggest planet handily outshines the smallest by a factor of 7.
Binoculars will prove to be most beneficial in making a sighting of these two planets against the bright twilight backdrop about a half hour before sunrise.
May 25: Supermoon!
On this date at 10 p.m. EDT, the moon will arrive at its closest point to the Earth in 2011: A perigee distance of 222,022 miles (357,311 km) away. A little over 9 hours later, the moon will officially turn full (and undergo a total eclipse. See below).
The near coincidence of the full moon with perigee will result in a dramatically large range of high and low ocean tides. Any coastal storm at sea around this time will almost certainly aggravate coastal flooding problems. Such an extreme tide is known as a perigean spring tide, the word spring being derived from the German springen — to "spring up," not a reference to the spring season.
May 26: Total eclipse of the moon
This total lunar eclipse favors the Pacific Rim, that is, the geographic area surrounding the Pacific Ocean. The Pacific Rim covers the western shores of North America and South America, and the shores of Australia, eastern Asia and the islands of the Pacific. Hawaiians get a great view with the eclipse happening high in their sky in the middle of the night. Across North America, western regions will be able to see the total phase and a part of the closing partial stages before moonset intervenes.
Central regions will be able to watch the start of the partial stages up to (or almost to) totality before the moon sets. Eastern regions must be content with perhaps a small scallop of darkness appearing on the moon's left-hand edge, or perhaps only a faint shading – the result of the Earth's penumbral shadow. The moon will pass well to the north of the center of the Earth's dark umbra; the uppermost part of the moon will be only 21 miles (34 km) from its outer edge. That's why totality will last only 14.5 minutes.
June 10: Ring of fire' annular solar eclipse
Because the moon will be situated at a distance of 251,200 miles (404,300 km) from Earth during this "ring of fire" solar eclipse, the lunar disk will appear somewhat smaller than the sun; 5.7% smaller to be exact.
As such, when the moon passes squarely in front of the sun, it will not totally cover the face of the star, but instead a ring of sunlight will remain visible. Hence, the term “annular” eclipse, derived from the Latin "annulus" meaning ring-shaped. Call it a "penny-on-nickel effect" with the nickel representing the sun and the penny, the moon.
This will be a rather unusual eclipse in that the path of annularity tracks in a strange manner: northeast, then north and finally in a northwest direction, through central and northern Canada, northwest Greenland, past the North Pole and finally ending over northeast Siberia. For those who live in New York State, New England, as well as southern portions of Ontario and Quebec, there will be an opportunity to see a most unusual sunrise this morning as the sun will rise looking like a crescent with cusps pointed upward. Toronto will see 86 percent of the sun's diameter eclipsed, 85% in Montreal and 80% for New York and Boston. The closing stages of the eclipse will be visible from Minnesota, the Great Lakes and Ohio Valley, as well as the Carolinas and Mid-Atlantic States.
Aug. 11-12: Perseid meteor shower
These overnight hours will be the prime time to watch for this, the Old Faithful of the midsummer sky: the Perseid meteor shower.
The best time to watch will be after the moon sets around 10 p.m. local daylight time, leaving the rest of the night dark for these swift streaks of light. The Perseids produce about one meteor per minute under dark country skies and occasionally will produce outstandingly bright meteors, called fireballs, or exploding meteors, called bolides.
Mid-September to end of 2021: The Venus show
The most dazzling of planets starts 2021 in poor fashion. Venus starts low in the southeastern dawn sky; sinks out of sight behind the sun in March and April. Reappearing in the sunset sky, it hangs there at only moderate height — sliding southward and coming gradually nearer and brighter but still setting before the sky becomes fully dark.
Finally, in mid-September, it remains in view after twilight ends and then in early November it suddenly vaults as if off a springboard into evening prominence, attaining its greatest brilliance in early December and with great fanfare calling attention to itself each evening during the Christmas season before plunging back toward the sun early in 2022.
Nov. 19: A near-total eclipse of the moon
North America is in an excellent position to see this eclipse. It will take place in the predawn hours with the visible stages ending before moonset.
The moon will slide through the southern portion of the Earth's dark umbra and at greatest eclipse all but 2.6% of the moon's diameter will be immersed in the shadow. Because some of the sunlight striking the Earth is diffused and scattered by our atmosphere, the Earth's shadow is not completely dark. Enough of this light reaches the moon to give it a faint coppery glow. Combined with the remaining uneclipsed yellow sliver, will create what some call the "Japanese Lantern Effect"; a strikingly beautiful sight for the naked eye, or viewing with binoculars or a small telescope.
The very beginning stages of the eclipse will be visible from the United Kingdom and parts of northern Europe prior to moonset. Eastern Asia and Australia will also see it after moonrise later that evening.
Dec. 4: Total eclipse of the sun
The final eclipse of 2021 will be visible only from the icy continent of Antarctica. The path of totality, averaging 265 miles (427 km) wide, will sweep inland south-southwest from the Weddell Sea, passing over Berkner Island and the Filchner-Ronne Ice Shelf, then continuing across West Antarctica, darkening the Executive Committee Range (a mountain range consisting of five major volcanoes), before moving offshore at the Ross Sea.
For even the most ardent eclipse chaser, this will prove to be a tough assignment, although a few hardy souls did see the last total solar eclipse visible here (in 2003) from the ground, while others overflew this frozen land in commercial aircraft.
An associated small partial eclipse can be glimpsed from parts of South Africa, Namibia, and Botswana, as well as Tasmania and southern sections of New South Wales and Victoria in Australia and a small slice of southernmost New Zealand and adjacent Stewart Island.
Dec. 13-14: The Geminid meteor shower
The Geminid meteor shower is due to reach its 2021 peak during the predawn hours of Dec. 14, when 60 to 120 slow, graceful meteors per hour may be seen under dark sky conditions. The Geminids are among the very few showers that perform well even before midnight, but this year the light of a gibbous moon will hamper pre-midnight observations.
In fact, the moon will continue to be a factor until it finally sets just around 3 a.m. local time. But fortuitously, that's probably the very best time to watch since the constellation of Gemini — from where the meteors appear to fan out — stands nearly overhead. Small and rather faint meteors will likely dominate leading up to their predicted maximum. Then, during and after maximum, bright meteors and even occasional spectacular fireballs should appear.
- Space Calendar 2021: Sky Events, Missions & More
- How to Catch the Next Eclipse: A List of Solar and Lunar Eclipses in 2021
- The Brightest Visible Planets in the Night Sky: How to See them (and When)
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.