May skies offer planet trio
This month we are offered an amazing trio of planets in the early evening sky. As the month progresses, Jupiter begins sinking toward the western horizon while Venus slowly begins to climb in the western evening sky. Beginning around mid-month, Mercury joins in on the fun as it rises above the western horizon. On the 19th, the three bright planets form a line less than 13 degrees long.
Mercury is about three degrees above the horizon about a half hour after sunset you may need binoculars to see it), with Venus about four degrees higher and to the left, and Jupiter about nine degrees higher and to the left of Venus.
The fun really begins over a six-night stretch from May 24-30. Over this six-night period, the three planets, while moving relative to each other, will always fit within five-degree circle. Mercury shining at magnitude -0.9, with Venus at -3.9 and with Jupiter at -1.9 should form a brilliant trio above the western horizon.
On the 31st things change rapidly as Jupiter sets less than half an hour after the sun. At this time the trio forms another diagonal straight line. Venus is 4.5 degrees lower and to the right of Mercury and Jupiter is 3.5 degrees below and to the right of Venus. Jupiter will soon be lost in the glare of the sun.
Saturn rises just before sunset at the beginning of the month and will be visible, at magnitude +0.3 for most of the night. Its beautiful rings remain open so as to offer spectacular views through small telescopes. Look for Saturn in the south-southeast about 15 degrees from the bright star Spica in the constellation Virgo. Mars is still lost in the glare of the early morning sun. The moon will be last quarter on the 2nd, new on the 9th, first quarter on the 18th, full on the 25th and last quarter again on the 31st. Looking west about 30 minutes after sunset on the 10th through the 12th, the very thin crescent moon is very close to Venus on the 10th (you might need binoculars for this) and brackets Jupiter on the 11th and 12th.