How To See Five Planets In February

Mercury joins Venus for a couple weeks at dusk this month. 25° = 2 ½ fists marked off against the sky with your arm fully extended. 5° = three fingers held together horizontally at arm’s length. Find your sunset time so you can plan a Mercury visit. Stellarium

Venus occupies center stage in the evening sky but soon gets some company. Mercury enters the scene this week and next, poking a tentative head above the southwestern horizon two-and-a-half fists to the lower right of Venus. The planet will be quite bright at magnitude –1.0 — a near twin to Sirius —  but low altitude and the twilight glow will make it appear fainter. Still, you should have no problem spotting the shy planet as long as you have a clear view of the west-southwest sky down to within a few degrees of the horizon.

This photo of Mercury was taken by NASA’s orbiting MESSENGER space probe. The prominent rayed crater at center right is Debussy, named for French composer Claude Debussy. Mercury is a small, rocky planet only a little bigger than the moon and takes 59 days to spin once on its axis. Almost three times closer to the sun than Earth, the planet’s daytime temperature climbs to 800° F (430° C). At night, the thermometer dips to –290° F (–180° C) because it has almost no atmosphere to ameliorate temperatures. Mercury is beautiful to look at but no friend to life as we know it. NASA

Because Venus is so easy to see we’ll use it as a pointer to Mercury, which glimmers about 5° above the horizon 45 minutes after sunset. Slide downward and right from Venus toward the lingering glow of sunset, and you’ll spot a starlike point of light in the orange afterglow. That’s the innermost planet staring back! Mercury is always teasing us observers, making us work a little harder to find it that the other naked-eye planets.

There are two reasons for this. Mercury is relatively far away (twice as far as Venus) and orbits the sun closely. Its greater distance means we see both bodies along similar lines of sight, so they appear closer together. That and the fact that it already orbits nearer the sun than any planet, and you can understand why Mercury never gets far from the sun.

Like a dog on a short leash attached to a lawn stake, the planet runs around the sun in tight circles, never leaving the twilight glow of dusk or dawn. Venus on the other hand, orbits further from the sun and comes much closer to the Earth, so it really stands out on its own. Of course, it doesn’t hurt that Venus is 100 percent cloud-covered — clouds are efficient reflectors of sunlight.

Mercury will climb higher in the west in the coming evenings to a more comfortable 10° altitude by Valentine’s Day before sinking back toward the sun. If you’re struggling to see the planet because of haze, bring binoculars. Focus them sharply on Venus first and then hunt for the shy guy.

An arc of planets — joined by Antares in Scorpius — greets dawn skywatchers 45 minutes before sunrise Tuesday morning Feb. 4. Saturn, VERY low in the southeastern sky, will be much easier to see an hour before sunrise by Valentine’s Day. All four of Jupiter’s bright moons lie to the lower left (east) of the planet Monday morning (Feb. 3). Stellarium

Dawn is not without its planetary pleasures. Early risers can spy three of these wandering stars during morning twilight. Red Mars and creamy Jupiter are easiest. Because of its low altitude I recommend binoculars for Saturn. Follow the arc from Mars to Jupiter and down toward the southeastern horizon to catch the ringed planet. Saturn will need another week to wrest itself from the bright glow of morning twilight into naked-eye visibility.

If you’re looking for a special Valentine’s Day gift, wake your special lady or man on that morning and lasso the trio the way Jimmy Stewart offered Mary the moon in “It’s a Wonderful Life.”

Clear skies!

3 Responses

  1. Edward M Boll

    I have been posting degrees of Elongations nightly. I right now have Mercury at 16 degrees, and Saturn at 19 from the Sun. I take the number of minutes different from the Sun at rise and set. I add them together and then divide by 8 to get the number of degrees. Not sure if this is the right formula, I have been very accurate using it.

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