Skywatch Line for Friday, February 21, through Sunday, February 23, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, February 21, through Sunday, February 23, written by Sam Salem.
On Friday, Sun rises at 6:43am and sets at 5:35pm; Moon rises at 2:08am and sets at 10:38am.
On Saturday, the waning Moon will lie near Antares, Heart of the Scorpion. Look east before sunrise. Watch for three moderately bright stars above Antares, known collectively as the Scorpion’s Crown.
The waning crescent Moon will approach, and then enter, the asterism of the Teapot of Sagittarius on Sunday and Monday morning. Look for them before dawn.
Venus, magnitude –4.8 in the constellation of Pisces, shines as the bright “Evening Star” in the west during and after twilight. It sets about two hours after dark. In a telescope Venus is a crescent about 25% sunlit. Venus is enlarging week by week as it swings toward Earth.
Mars, magnitude –0.6 in the constellation of Gemini, is a steady orange spark high in the east. It continues to fade. As darkness deepens, watch for fainter Pollux and Castor to emerge lower left and left of it, respectively. The triangle the three make is now almost isosceles, with Mars as its long point. The triangle becomes exactly isosceles for several days around Saturday. It stays unchanged for that long because Mars comes to the stationary point of its retrograde loop right around then, on February 24th.
Jupiter, magnitude –2.4 in the constellation of Taurus, shines bright white, 36° west along the ecliptic from Mars. It dominates the high south after dusk near Aldebaran and the Pleiades. Jupiter forms an almost exact right triangle with them this week and next.
Later in the evening, Jupiter moves lower in the southwest. It sets in the west-northwest around 2am.
Saturn, magnitude +1.1, is about two fists down below Venus in late twilight, lower every day.
Uranus, magnitude 5.7 at the Taurus-Aries border, is still high toward the southwest right after dark, 18° west of Jupiter along the ecliptic.
This is a good weekend to look for the zodiacal light, now that the early-evening sky is moonless and the ecliptic tilts high upward from the western horizon at nightfall. From a clear dark site with clean air, look west at the end of twilight for a dim but huge, tall pyramid of pearly light. It’s tilted to the left, aligned along the constellations of the zodiac. Zodiacal light is sunlit interplanetary dust, originating from old asteroid collisions and long-evaporated comets, orbiting the Sun near the ecliptic plane.
Five constellations are rising upright in a row from the northeast to south during the night. These are Ursa Major with the Big Dipper as its brightest part, Leo the Lion in the east, Hydra the Sea Serpent in the southeast, Canis Minor the Little Dog higher in the south-southeast, and bright Canis Major the Big Dog in the south.