Two planets and a star far outshine all competitors at dusk in February.
They are: Venus, of magnitude -4, low in the west-southwest, shifting toward the west and slowly gaining altitude as this month progresses; Jupiter, of magnitude -2.6, starting very low in the east-northeast, moving into the east and climbing about 1 degree higher each day (if viewed at the same stage of twilight daily); and blue-white Sirius, the “Dog Star” and brightest of nighttime stars, twinkling at magnitude -1.4 and ascending through southeast toward south-southeast at dusk as February runs its course.
Follow these three bright objects at dusk in coming months. Sirius will disappear into the west-southwest twilight glow during May, while Venus and Jupiter remain in view until at least late in July.
February’s other naked-eye evening planet is Mars, appearing as a red “star” of magnitude +1.2 to +1.3, not far from Venus all this month. Look about 9 degrees to the upper left of the brighter planet on Feb. 1, to 3 degrees to the lower right on Feb. 28. Both planets move rapidly against background stars, and remain within 10 degrees of each other for six weeks, starting on Jan. 31.
Stars at dusk: Look for the huge Winter Hexagon of Sirius-Procyon-Pollux-Capella-Aldebaran-Rigel. The noticeably red star Betelgeuse is within the Hexagon. Find the three-star belt of Orion, the hunter, midway between his shoulder, Betelgeuse, and his foot, bluish Rigel. The belt extended southeastward locates Sirius. Extend the belt in the opposite direction, bending north a bit, and you’ll find Aldebaran, eye of Taurus, the bull. Go farther to find the Pleiades, or Seven Sisters, a wonderful sight for binoculars!
Moon at dusk in early February: On Feb. 1 at dusk, less than two days before full, the moon appears between Pollux, the brighter of the Gemini twins, and Procyon, the Lesser Dog star. (The moon will return to the same place among the stars in just a little more than 27 days, but at a lesser phase, on the final evening of this month.) On Feb. 3, the moon, just past full and rising a few minutes after sunset, appears 5-6 degrees south (to the right) of bright Jupiter. The moon rises about an hour after sunset on Feb. 4, and nearly an hour later nightly for the next several evenings. Rather than staying up late to watch moonrise, shift your viewing time to morning, and follow our satellite in the morning twilight, less than an hour before sunrise:
Moon in morning twilight:
Feb. 3: Nearly full moon, setting in the west to west-northwest, 10 degrees to the lower right of Jupiter.
Feb. 4: Moon just past full, low, just north of west, 7 degrees to the lower left of Jupiter.
Feb. 5: Moon low in the west, 5-6 degrees to the lower left of Regulus.
Feb. 9: Waning gibbous moon in the southwest, less than 4 degrees to the upper right of Spica.
Feb. 12: Moon just past last quarter phase in south, a little less than half full, 5 degrees to the upper right of Saturn.
Feb. 13: Waning crescent moon in the south-southeast, about 8 degrees left of Saturn and 8-9 degrees to the upper left of Antares.
Feb. 16: Thin crescent moon low in the southeast to east-southeast, 9 degrees to the upper right of Mercury.
Feb. 17: Last old very thin crescent moon very low in the east-southeast, 6 degrees to the lower left of Mercury.
The new moon, invisible near the sun, occurs on Feb. 18 at 3:47 p.m. The moon returns to evening sky on Feb. 19. About 40 minutes after sunset, look for the young, thin crescent about 9 degrees south of due west and 6 degrees up, 13-14 degrees to the lower right of Venus.
Be sure to catch the spectacular gathering of the crescent moon and two planets at dusk on Feb. 20, all within a 2 degree field. The 2-day-old moonwill be within 1.7 degrees to the upper right of Venus, with Mars in between them, 0.7 degrees to the upper right of Venus. Venus-Mars appear closest to each other the next evening, Feb. 21, as Venus passes 0.4 degrees south of Mars. That same evening, the crescent moon will appear 14-15 degrees above the pair; as darkness falls, binoculars will show another planet, sixth-magnitude Uranus, just 2 degrees below and slightly right of the moon.
On Feb. 24, the fat crescent moon passes 8 degrees to the south of the Pleiades, or Seven Sisters star cluster. By the next evening, the moon will have passed first quarter phase and will appear just over half full, within 2 degrees to the east of Aldebaran, eye of Taurus the bull. As we look out the rear window of Spaceship Earth on Feb. 24-28, we are speeding away from the Hyades star cluster with Aldebaran in the foreground. On the night of Feb. 28, the waxing gibbous moon will lie about midway between Pollux and Procyon.
February 2015 at dawn: For most of February, in the morning twilight, you can observe as many as three planets: Jupiter, before it drops below horizon in the west-northwest near end of third week; Saturn, in the south all month; and Mercury, after it brightens to first magnitude early in second week. Look for these bright stars, also within the zodiacal belt, within a few degrees of the plane of Earth’s orbit: Antares, heart of Scorpius, to the lower left of Saturn; Spica to right of Saturn; and Regulus, heart of Leo, in the west, far to lower right Spica and upper left of Jupiter.
Other bright stars at dawn are Arcturus, high above Spica in the southwest sky; and the Summer Triangle of Vega-Altair-Deneb, climbing in the eastern sky. Brightest objects at morning mid-twilight for most of February, in order of brilliance, are: Jupiter (until it drops below the west-northwest horizon), Arcturus, and Vega. In the last week of February, Jupiter sets before middle of morning twilight, but Mercury becomes a close match in brightness to these two stars.
A View out the Front Window of Spaceship Earth!
Step outside on February mornings about an hour before sunrise, and visualize the motion of our planet in orbit around the sun.
In what direction are we heading? The sun is below the eastern horizon, below the brightest twilight glow. If you could go to a place high “above” the solar system, high in the northern sky toward the constellation Draco, and look “down,” you would observe that the revolutions of the eight planets around the sun, as well as the revolution of the moon around the Earth would all be counterclockwise.
On Feb. 6, Earth passes between sun and Jupiter, and that planet appears at opposition, 180 degrees from the sun. Note the star Regulus, 12 degrees to the upper left of Jupiter that morning. Twelve days later, on Feb. 18, Earth passes between Sun and Regulus, and that star takes its turn at opposition. If you look each morning at the same stage of twilight, Jupiter and Regulus appear lower daily, as we overtake and then look back at them.
On Feb. 23, the revolution of Spaceship Earth around the sun is carrying us toward Saturn. By Feb. 28, Earth is heading toward a point 5 degrees north of Antares in the predawn sky (and away from a point 5 degrees north of Aldebaran in the evening sky). As we travel around our curving orbit and overtake Saturn on May 22, that planet will appear at opposition and be above the horizon all night, and on May 31, Antares will be at opposition.
Mercury, an inner planet moving faster than Earth, passed nearly between Earth and Sun, inferior conjunction, on Jan. 30, and then moved ahead of us to emerge into the morning sky in February (faint at first, while displaying a backlighted crescent). Mercury reaches greatest elongation on Feb. 24. Next heading toward the far side of the sun, Mercury will drop below the horizon at morning mid-twilight by mid-March, and finally pass beyond the Sun at superior conjunction on April 9.
Wishing you clear skies to enjoy the ride on Spaceship Earth!
Robert C. Victor was a staff astronomer at Abrams Planetarium at Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs. Robert D. Miller, who provided the twilight charts and the planet orbit charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.