Skywatch Line for Friday, February 27, through Sunday, March 1, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, February 27, through Sunday, March 1, written by Sam Salem.
On Friday, Sun rises at 6:34am and sets at 5:42pm; Moon sets at 4:30am and rises at 1:18pm.
On Friday, the Moon passes 4° north of Jupiter at 1am. Both are in the constellation Gemini and sinking slowly in the west. The Moon and Jupiter hang below the two brightest stars in Gemini, Castor and Pollux, which mark the Twins’ heads. Castor is the rightmost star with a slightly blue-white hue. This multi-star system can be split into two in any telescope, showing a pair of A-type stars. Pollux is located to Castor’s left as Gemini sets. Pollux’s hue is more orangey-yellow. This is because Pollux is a cooler K-type giant star.
The waxing gibbous Moon rises after sunset on Sunday. It will be close to Regulus, the brightest star in Leo the Lion. Regulus marks the bright dot at the bottom of the backward question mark that forms Leo’s Sickle. It represents the lion’s head and shoulders. They’ll be visible through dawn the next morning.
Mercury and Venus pass each other quite low in the western twilight this week. Venus, magnitude –3.9, is the lowest of the two. It gets the slightest trace higher in the sunset afterglow each day. Mercury, much fainter and fading fast, stands 4½° to Venus’s right or upper right at their conjunction on Friday. Mercury fades fast from magnitude –0.2 last week to +1.6 this Friday. That’s a four-fifths drop in brightness.
Saturn, magnitude +1.0, sits above Mercury and Venus and a bit left. It’s sliding down toward them day by day, on its way to passing Venus by 1° on March 7th and 8th. By then Mercury will be long gone.
Jupiter glares at magnitude –2.5 nearly overhead toward the south in early evening, and less high in the southwest later in the evening. In a telescope it’s still 43 arcseconds wide, though it’s shrinking and fading slightly as Earth pulls farther ahead of it in our faster orbit around the Sun. Jupiter doesn’t set until far into the early morning hours.
On Friday, use a telescope to see Jupiter and its moons. Depending on the time, you might be able to see three or four of its Galilean moons. Throughout the morning, Ganymede and Europa lie to the planet’s west, while Callisto is off to its east. Io passes behind the planet’s disk in an occultation around 1am and spends a little over two hours behind the Jupiter.
On Friday, Asteroid 7 Iris reaches opposition at 1pm. 7 Iris is a large main-belt asteroid orbiting the Sun between Mars and Jupiter. It is the fourth-brightest object in the asteroid belt. 7 Iris is classified as an S-type asteroid, meaning that it has a stony composition.
Sunday marks the 60th. anniversary of the first spacecraft to impact Venus. On March 1st.1966, the mission of the Soviet Union’s unmanned spacecraft Venera 3 (Venus 3)
was a partial success when it reached Venus and automatically released a small landing capsule intended to explore the planet’s atmosphere during a parachute descent. However, contact had been lost since 16 Feb 1966. Although no data was returned before the capsule impacted, it became the first man-made object to touch the surface of another planet. Failure is believed due to overheating of internal components and the solar panels.