This is the Skywatch Line for Monday and Tuesday, April 11th and 12th
The Sun sets at 7:33 PM; night falls at 9:15. Dawn breaks at 4:37 AM and ends with the Sun rising at 6:18.
The Moon dominates the sky on both nights. Monday, the five-day-old Moon blazes at minus 8.3 magnitude in Taurus; Tuesday finds it in Gemini shining brighter at magnitude minus 9.1. It sets after midnight on both nights.
Jupiter still resides in Leo; it rises about 4 PM and lies under Leo’s belly. Jupiter is best seen at about 10:37 PM. While the binocular observer can see the planet and some of its moons, a telescopic astronomer can make out the weather bands, witness the Jovian moon Io disappear behind the giant planet at 2:26 AM, Wednesday and see the Great Red Spot (a giant storm on Jupiter) at 11:49 PM Tuesday.
The twilight sky also hosts Mercury. As mentioned last week, this is Mercury’s best appearance of the year. It hovers at about eleven degrees above the western horizon and shines at magnitude minus 0.6. It sets at about 9:11 PM. There are no brighter stars in Mercury’s neighborhood, so identification should be easier. In a telescope it appears about 62 percent illuminated.
Mars rises in Ophiuchus at about 11:15 PM and is best observed at approximately 4 AM. Mars continues to brighten and grow larger in our telescopes in preparation for its May opposition. Saturn, also in Ophiuchus, rises a half hour after Mars. Saturn shines at a sedate 0.3 magnitude. Compare Mars’ color with that of the star Antares in nearby Scorpius. Also note the distance between Saturn and Mars; they come closer to each other until April 17th.
Jupiter, Mars and Saturn remain up the rest of the night.
Jupiter points to another constellation to Leo’s right – Hydra. Hydra begins with a diamond-shaped head and the rest of the body extends southward. In fact, Hydra is the longest and largest constellation. One must travel well South to enjoy Hydra to its fullest extent. Hydra is unique in that two smaller constellations ride atop it: Crater, the Cup, and Corvus, the Crow. In Greek mythology, Hydra is a mythical water snake. It attacked Jason and his shipmates on the good ship Argo. In Roman myths, Corvus was commanded by Apollo to bring a cup of water, but got sidetracked by ripening grapes. Corvus tried to excuse his tardiness by blaming the snake. Do not confuse Hydra with the similar sounding constellation Hydrus. Hydrus is relatively modern. It was one of many, invented by explorers who ventured below the equator for the first time.