Skywatch for the week of April 27, 2020
Tues Apr 28, 2020 NAME THAT CONSTELLATION! Can you identify the thirtieth largest constellation? It’s bordered on the north by Lynx the Bobcat and Auriga the Charioteer; on the east by Cancer the Crab; on the south by Canis Minor the Lesser Dog and Monoceros the Unicorn; and on the west by Orion the Hunter and Taurus the Bull. This constellation was created thousands of years ago, and its brightest stars trace out a long rectangle in the heavens. In the Middle East, these stars were seen as a stack of bricks, but in Italy, they represented Romulus and Remus, the founders of Rome. The Greeks named them Castor and Pollux, which are also the names of this constellation’s two brightest stars, and tonight the waxing crescent moon lies between these twin brothers. Can you name this star pattern, the third constellation of the zodiac? It is of course, the Gemini, visible in the southern sky after sunset.
Wed Apr 29, 2020 SUN IN ARIES The earth revolves about the sun, which causes the sun to slowly drift through our sky from west to east. The sun has now entered the constellation Aries, the Ram. This means that because of the earth’s revolutionary motion, the sun is now directly between us and the stars which make up Aries. This obviously is a bad time to be looking for the constellation of the Ram, because the bright sun blocks our view of this part of space. If today’s your birthday, you may have been told that you’re a Taurus, meaning the sun was in Taurus when you were born. But the sun isn’t in Taurus, it’s in Aries, and will be for the next several weeks. When astrology was in its heyday thousands of years ago, the sun would have been in Aries, but because there’s a very slow wobble in the earth’s rotational axis, all the zodiacal signs have been offset by one constellation, turning bulls into sheep, sheep into fish, and so on.
Thu Apr 30, 2020 THE HUBBLE SPACE TELESCOPE Thirty years ago, on April 25, 1990, the Hubble Space Telescope was put into orbit. It had been carried up 400 miles above the earth’s surface by the space shuttle Discovery the day before, and about a month after its release it began sending back images. There were problems with the telescope at first, mainly because its primary mirror was not quite the right shape. Still the Hubble worked about as well as the biggest ‘scopes on earth, and when corrective optics were put in place two years later, it began out-performing all other instruments. In the past 30 years, Hubble has seen ammonia iced storms on Saturn, the impact of a comet on Jupiter, Pluto’s icy surface, nearby stars, supernovas, star clusters, distant galaxies and quasars, and so much more!
Fri May 1, 2020 SPRING CROSS QUARTER DAY, VIRGO AS SKY MARKER Divide the year up into four parts or quarters. Each quarter is marked by the beginning of a new season. The quarter days of Summer and Winter are known as solstices, when the noontime sun reaches its highest or lowest altitude in the sky; while during the equinoxes of Spring and Autumn, nights and days are of fairly equal length. Now divide those seasons in half and you get cross-quarter days, the midpoints of each season. May 1st marks the cross-quarter day for Spring, called Beltane in the old Celtic calendar. In traditional maypole dances, everyone moved clockwise around the maypole, mimicking the sun’s motion across the sky through the day. At the beginning of spring, the stars of the constellation Virgo, the springtime maiden, appeared in the east after sunset. Now Virgo is well up in the southeastern sky, and at summer’s beginning it will be high in the south. But as autumn approaches, Virgo will sink into the west, and we’ll lose sight of it as we move toward winter.