Butler County Times Gazette
  • Looking Up: A nice orange star and red Mars

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  • Coming up in the east in late April evenings is the constellation Bootes, the Herdsman. Its principal stars form what looks more like a kite than someone who herds animals. Its brightest star, Arcturus, shines a lovely yellow-orange hue. Over to the right this season is an even brighter, red-orange planet, Mars.
    If you can find the Big Dipper, Bootes is a cinch, as the top of this "kite" lies immediately off the end star on the Big Dipper’s handle (which, by the way, is known as Alkaid). At the lower end of the kite figure is Arcturus.
    The Big Dipper, which constantly circles a point next to the North Star in our northern sky, serves as a very handy pointer. In addition to the front stars of the bowl pointing right at the North Star, the handle of the Dipper points down to the bright star Arcturus. Continue your swing past Arcturus to another bright, blue-white star, known as Spica. In the spring of 2014, the planet Mars is shining bright, above Spica when it is viewed in the east.
    Arcturus is among the night sky's brightest stars, magnitude -0.04.
    The lower the number, the brighter the star; for some odd reason, the magnitude scale does not begin with zero for classifying stars; these four mentioned are all brighter than 0.0. The faintest magnitude you can normally see with unaided eyes, on a good night, is +6.
    Arcturus presently lies 36.7 light years from the sun; it takes that many years for the starlight to reach our eyes. Astronomical distances are always relative (Dr. Albert Einstein would be pleased.) While we list a star at, say 36.7 light years, it is actually constantly changing. The starry sky seems to our perspective, without sophisticated equipment, quite static. Constellations year after year appear the same in outline; the Big Dipper our great-great-great grandfather saw appeared the same as you will see it tonight. In actuality, the stars are rushing around the common galactic center. Thousands of years ago, the constellations we know today would be slightly different. Arcturus has the unique distinction of having the largest proper motion of any bright star, across the sky. The famed astronomer Sir Edmond Halley first detected the motion of this star, in 1718.
    In 1933 the light of Arcturus was used to open the World’s Fair in Chicago. The star was chosen as it was thought that light from Arcturus had started its journey at about the time of the previous Chicago fair in 1893.
    The star is mentioned twice in the Bible, in Job 9:9 and Job 38:32.
    The star is an orange-red giant. Stars differ greatly in size, composition, temperature, luminosity and color. Astronomers suspect they go through stages over the eons, as they use up their hydrogen to emit heat and light. Depending on a host of circumstances, they may eventually end in a supernova explosion or as a small, dim dwarf star.
    Page 2 of 2 - Last-quarter moon is on April 22.
    Feel free to write me at news@neagle.com.
    Keep looking up!
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