It’s 5:19 p.m. on February 14, 2022, and the Sun is setting over Montreal. The almost-full Moon rose two hours ago and is already visible. With each passing minute, it stands out better in the darkening twilight. Soon, we’ll discover the Moon’s nighttime companion on this Valentine’s evening. Who could it possibly be?
Is it a planet?
Very low on the horizon, a mere 5 degrees high 30 minutes after sunset, you may just be able to spot Jupiter’s fading brightness in the ongoing glow of the Sun. Earlier this month, on February 2, we observed the thin first crescent Moon (just one and a half days after the new Moon) between Jupiter and the southwestern horizon. But tonight, Jupiter is gearing up for another rendez-vous. Having been a fixture in the evening sky for months, the giant planet is poised to leave the celestial stage for a few weeks, swallowed up by the Sun’s glare while in superior conjunction.
Jupiter’s decline signals the end of bright planets visible in the evening sky—until the end of summer, that is. But early risers can still enjoy a plethora of planets. By night’s end, at around 5 a.m. in mid-February, dazzling Venus will emerge above the southeastern horizon. These days, the planet climbs nearly 20 degrees above the horizon at dawn—the peak altitude it reaches during its current morning apparition, which lasts until October.
A few minutes after Venus rises, Mars can be spotted below the brilliant planet. Both are in the constellation Sagittarius, but the tiny Red Planet is much fainter. The pair cozy up to one another until the middle of next month and will be in conjunction in (ecliptic) longitude on February 18.
At 6 a.m., a third celestial body will join the dance. A small, rocky object with no atmosphere and whose grey surface is riddled with craters. Could it be the Moon? No, it’s Mercury, much farther away and dimmer. Although Mercury can never compete with the Moon in our sky, the best time to observe the tiny planet this winter will be during the mornings around its greatest elongation on February 16.
The waning crescent Moon will only join the Venus-Mars-Mercury trio at the end of February. The planetary paparazzi will be on the lookout for many delightful alignments between February 26 and 28 at dawn.
So, where can we find the Moon’s valentine? By turning our gaze far beyond the Solar System.
Is it a star?
We’re now back to early evening on February 14. As we face the setting Sun and try to spot Jupiter in the twilight glow, behind us in the east, the brightest stars in the winter sky begin to emerge, one by one.
Sirius, in the constellation Canis Major, is the brightest star in the night sky; it shines like a beacon at only a dozen or so degrees high in the southeast. Capella, much higher in the sky (about 70 degrees) and slightly further east, is the brightest star in the constellation Auriga.
Rigel, with its bluish white glow, and Betelgeuse, iconically reddish, are both located in the famous constellation Orion, slightly to the west of and about 20 degrees higher than Sirius. Procyon, further east and slightly higher than Sirius, is the only very bright star in the tiny constellation Canis Minor (“Lesser Dog”).
Aldebaran is another characteristically reddish star, located in Taurus, high up (about 60 degrees) in the southeast above the stars of Orion. Castor and Pollux, Gemini’s twins, shine at about 40 degrees high due east, between the constellations Auriga (Capella) and Canis Minor (Procyon).
These winter stars all appear even before the sky is dark enough to spot Ursa Major. Grouped together, the stars form a prominent pattern known as the Winter Hexagon, an asterism connecting the six vertices Sirius, Rigel, Aldebaran, Capella, Pollux and Procyon, with Betelgeuse in the middle.
While the Moon regularly swings by the Winter Hexagon, only Aldebaran is sometimes graced by its presence at the time of a conjunction, or even a rare occultation. Could it be the Moon’s soul mate on this special Valentine’s evening? Our satellite is actually within close range on the 9th, even occulting the star Kappa Tauri, between Aldebaran and the Pleiades. Alas, Aldebaran will have to wait until 2033 for its next dance with Selene.
As night continues to settle in, other stars pop into view across the sky. The bowl of the Big Dipper points the way to the North Star. Located between Rigel and Betelgeuse, the three stars of Orion’s belt also make their appearance, forming a slanted line that points downward and left toward Sirius, and upward and right toward Aldebaran. Slightly farther out on the line past Aldebaran is a little group of stars known as the Pleiades.
Is it a celestial object?
At the end of astronomical twilight, about an hour and a half after sunset, the Moon can be spotted shining due east in a region of sky devoid of bright stars: the constellation Cancer. Despite being the faintest constellation in the zodiac, Cancer is easy to find thanks to its showy neighbours: the Gemini twins Castor and Pollux to its right, and the Lion’s head shaped like a backwards question mark to its left. For its part, Cancer has a subtle charm that goes straight to the heart…
Nestled right in the centre of the constellation is an open star cluster called the Beehive Cluster (M44), a group of around 1,000 young stars still gravitationally bound after their birth. Take a look on a moonless night, in a dark country sky, and you’ll see a hazy, nebulous patch of light. But the Moon will wash out even the biggest and brightest of clusters on that night. However, if you point binoculars 3 degrees below the Moon, you’ll get a clear view of the swarm of stars, twice as wide as our satellite and appearing to embrace it. Within the cluster are dozens of stars glittering like precious crystals. And there you have it, the sweetheart who will make the Moon swoon tonight—if only for a brief honeymoon!