Jupiter Visits the Crab

Since last summer, Jupiter has been visiting the constellation Cancer, the crab. These two cosmic residents are a study in contrasts, and a reminder of how Cancer became a constellation. Brighter than any star, Jupiter is one of the night sky’s most brilliant objects. Cancer, however, is composed of only faint stars and is the least conspicuous constellation on the ecliptic. Jupiter’s pass through Cancer every 12 years is a reminder of the story of how Cancer came to be in the night sky. In the religions of ancient Greece and Rome, Jupiter (also known as Zeus) was the god of the heavens and earth. In addition to his goddess wife, he had many lovers (some other goddesses, some mere mortals), and thus many offspring. The progeny he fathered with goddess mothers were fully gods, like Mars and Mercury. Those fathered with mortals were demigods–part mortal, part divine. One of Jupiter’s most notable demigod sons was Hercules who displayed great strength and courage through many heroic adventures, one of which was killing Hydra, the water snake. During the battle, Hercules was pinched on his toes by Cancer, which Hercules promptly stepped on and crushed. Another god, feeling sorry for the lowly crab, gave it immortality in the sky. Situated between the Gemini twins and Leo, the lion, Cancer’s primary claim to fame is its location on the ecliptic (known in astrology as the zodiac). The ecliptic is the path taken by our Sun across our sky through the course of a year. Of course, we can’t see the Sun pass through constellations, but, since Earth and the other planets (as well as the Moon) orbit on nearly the same plane, the planets (and Moon) also pass through the same constellations as the Sun. So like all ecliptic constellations, Cancer is regularly visited by the planets and the Moon. Cancer is also home to two nice star clusters, one of which is among the loveliest in the night sky’the Beehive (also known as Praesepe, the Manger, and M44). To the naked eye the Beehive appears as a subtle fuzz of light the size of the full Moon. Binoculars reveal a swarm of stars, giving rise to its name. Although the stars forming Cancer are too faint to be seen except under dark skies, Jupiter can now help identify its location’even if you can’t see it. Around 10 p.m. they are situated half way up in the west, with Jupiter being the brightest star-like object in the night sky. As a special treat, a crescent Moon forms a triangle with Jupiter and the Beehive the evening of June 4. SKY CALENDAR ‘ May 28, Wednesday morning: A thin crescent Moon is to the upper right of Mercury and Venus near the eastern horizon shortly before sunrise. ‘ May 30, Friday: The new Moon produces an annular eclipse of the Sun which, unfortunately, is not visible from the U.S., except in Alaska. ‘ June 1, Sunday evening: A thin crescent Moon is above Saturn low in the west northwest soon after sunset. ‘ June 4, Wednesday evening: A crescent Moon is just above the Beehive star cluster and to the right of Jupiter. ‘ June, 6 Friday evening: The Moon is to the right of Leo’s brightest star, Regulus. ‘ June 7, Saturday evening: The Moon is at first quarter, poor for evening but good for morning stargazing. ‘ June 12, Thursday evening: A large gibbous Moon is above Scorpius’ brightest star, Antares, low in the southeast, and is to its lower left the next evening. ‘ June 13, Friday: The year’s only Friday the 13th is a bad luck day but only for the superstitious. PLANETS Mercury has joined Venus in the morning sky with both rising about an hour before sunrise in the east. Mars, now brighter than any star in the morning sky, rises at 1:30 a.m. Dominating the evening sky, Jupiter sets at 1 a.m. Saturn, which sinks into the evening Sun next month, sets at 10 p.m. Neptune and Uranus, neither of which can be seen with the naked-eye, rise at 1 and 2 a.m., respectively. Stargazer appears every other week. Paul Derrick is an amateur astronomer who lives in Waco. Contact him at 918 N. 30th, Waco, 76707, (254) 753-6920 or pjderrick @aol.com. See the Stargazer Web site at stargazerpaul.com.

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