Catch A Naked-Eye Comet!
(Updated July 17, 2020)
Few comets become easy naked-eye targets, so don’t miss your chance to see this one—it’s even visible under city skies! Comet C/2020 F3 (NEOWISE) was discovered on March 27 by the orbiting infrared telescope behind the NEOWISE mission—hence the comet’s nickname. Until early July, Comet NEOWISE was visible only from the Southern Hemisphere. Traveling northward, it reached perihelion on July 3, zooming past the Sun about as close as planet Mercury. Now, observers in the Northern Hemisphere get their chance to admire it. What a show!
Initially visible at dawn only, Comet NEOWISE has now become an evening sky object—no need to get up in the middle of the night anymore! To find it, you’ll need an unobstructed view to the northwest, as well as a clear, cloud-free sky in that same direction. Look for it near the end of evening twilight, at about 10:00 p.m., when the sky has darkened enough, but before the comet becomes too low and near the horizon. Start by locating the Big Dipper asterism, the famous star pattern in Ursa Major, or the Great Bear: over the next week or so, the comet will be moving through the Great Bear’s paws, between the dipper and the horizon. To the naked eye, the comet’s head appears as a fuzzy star, about 12 degrees above the horizon. With binoculars, enjoy the view of its yellowish dust tail, which extends almost vertically while arcing slightly to the right. For the night owls out there, Comet NEOWISE is still observable at the crack of dawn, low in the north-northeast at about 3:30 a.m., but its evening visibility is now better by far.
Comet NEOWISE is now moving away from the sun, which means it appears slightly dimmer every night. However, the comet is also approaching Earth until July 23, which will help maintain its naked-eye visibility for some time still. But don’t wait until it’s too late to have a good look at this rare celestial treat!
The summer sky abounds with magnificent constellations. Strictly speaking, the famous Summer Triangle is not a constellation, since the three bright stars that form the shape reside in three different constellations: Vega in Lyra, Deneb in Cygnus, and Altair in Aquila. However, two smaller, fainter constellations do lie within its borders: the Little Fox and the Arrow.
Sagitta, the Arrow, located slightly above Aquila the Eagle, is among the smallest of the 88 official constellations. It is comprised of five main stars in the shape of an arrowhead pointing eastwards. Many associate this constellation with the sixth task of the twelve labours of Hercules, which required the demigod to rid Lake Stymphalia of the monstrous birds that were feeding on human flesh. In fact, the constellation Hercules lies just west of the Summer Triangle.
Lift your gaze above the Arrow, near the middle of the Summer Triangle, and you’ll spot Vulpecula, the Little Fox. This constellation was introduced by the astronomer Johannes Hevelius in the 17th century. It was originally depicted as a fox holding a goose in its jaws, but when the International Astronomical Union condensed and standardized the constellations in 1922, only the fox survived. But the goose remains in spirit, as the brightest star in the constellation is officially named Anser, which is Latin for goose.
The constellation of the Little Fox is home to Messier 27, the magnificent planetary nebula otherwise known as the Dumbbell Nebula due to its shape. It consists of a shell of gas expelled by an aging star located about 4,000 light-years away. This nebula is visible with binoculars in dark skies, although a telescope will reveal it in all its splendour. To find it, start by locating the star at the eastern tip of the Arrow, then look straight up. Here’s an interesting historical fact: In 1967, Jocelyn Bell Burnell discovered the first known pulsar, PSR 1919+21, in none other than the constellation of the Little Fox.
The planets in July
Two planets emerge above the southeastern horizon at nightfall: Jupiter, the brighter of the pair, and Saturn, slightly below and to its left. They both reach opposition within days of each other (Jupiter on July 14 and Saturn on July 20) and will therefore be visible most of the night all month long. On the evening of July 5, the waning gibbous Moon will form a triangle with the two planets, with Jupiter above the Moon and Saturn lying to its left.
In July, Mars rises around midnight and will be visible in the second half of the night, until dawn. Currently located in the constellation Pisces, below the famous Great Square of Pegasus, the Red Planet dominates the heavens with its striking hue and brilliance in a region of sky devoid of bright stars. At around 1 a.m. on July 11, the waning gibbous Moon will sit to the right of Mars, then shift to the lower left of the Red Planet the following day.
Venus and Mercury in the morning sky
The dazzling planet Venus dominates the sky at the end of the night and at dawn. It rises above the east-northeastern horizon after 3:30 a.m. and can be found about 20 degrees high in the east at daybreak. From July 5 to 12, Venus glides through the Hyades cluster, a V-shaped group of stars located in the constellation Taurus, with the bright reddish star Aldebaran at one tip of the V. On the mornings of July 11 and 12, Venus will pass just one degree from Aldebaran.
The morning of the 17th, the lunar crescent will appear to the left of Venus. You may get lucky and catch a glimpse of Mercury just above the horizon. To locate the planet, look for it to the right of the very thin crescent Moon on the morning of July 19. The Moon and Mercury will be difficult to spot, but you can try using binoculars to scan the east-northeastern horizon about 45 minutes before sunrise.