STAR GAZER
THE INTERNATIONAL EDITION
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Horkheimer: Greetings, greetings fellow star gazers.
Well it's that time of year again when the night skies almost
shout "spring is here" because springtime's Leo the
Lion is chasing winter's Orion and replacing him as the major
constellation for early evening viewers. Let me show you.
Now most of you know that Orion the hunter is winter's most famous star pattern. Indeed if you go outside in early evening in December you'll see Orion climbing up the eastern skies as a celestial announcement of the imminent arrival of winter. And in the depths of winter, in January and February, Orion reaches his highest point in the heavens in early evening, almost bragging that he is master of the season. But then as March begins things start to change because all throughout March Orion slowly relinquishes his high flying position in early evening and by the beginning of April is tipped over on his side in the southwest almost hanging on to the sky for dear life as if he knows that in just a few weeks he will be gone from evening skies until next winter. And it is this position of Orion in the southwestern heavens in early evening that always tells us that winter is coming to an end.
And although I am always sad to see Orion's bright stars go, nevertheless I'm happy to see a much bigger although less bright constellation take his place almost overhead in early evening, Leo the Lion roaring that he is master now and that he will dominate spring skies. In fact if you go out any night in late March or April in early evening you will see Leo casually reclining almost overhead just as the ancient Egyptians depicted him in a regal sphinx like position, very self assured that winter and Orion will soon be history. His head and forequarters are indicated by a backward question mark with the bright blue white star Regulus marking his heart. His rear is marked by a triangle of stars with Leo's second brightest star Denebola marking his tail.
Now in ancient times lions were often associated with royalty. And in fact Leo's brightest star Regulus means "the little king". But little it is not. Some latest measurements indicate that it is more than one and a half times the diameter of our almost one million mile wide Sun. But because it is a much hotter star it is actually 140 times brighter. And because it is a whopping 80 light years away this means that when we look up at Regulus this spring we see the light that left it 80 years ago. Curiously, however, even though Denebola is twice as close, only 40 light years away, and even though it is much bigger than Regulus, it nevertheless appears dimmer than Regulus. Why? Because it is much cooler, only 20 times brighter than our Sun. Even so if we moved either Denebola or Regulus as close to Earth as our Sun is we'd all be crispy critters.
So welcome in spring the cosmic way. Simply go outside in early evening any night in late March and April look toward the southwest and you'll see Orion the master of winter on his way out and almost overhead, Leo the Lion, the king of spring. Keep looking up!
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Horkheimer: You can tell spring is here because Leo the Lion is replacing Orion. In early evening look southwest and you'll see winter's super star Orion the Hunter getting ready to exit while almost overhead Leo is roaring that he is the king of spring. Reclining like a giant cosmic sphinx Leo's two brightest stars put our sun to shame. His heart star Regulus is 4 _ times bigger and 140 times brighter, whereas his tail star Denebola is 2 times bigger and 14 times brighter. And think of this, if we replaced our Sun with either Regulus or Denebola we'd all be crispy critters. So welcome back springtime's Leo the Lion, and wave bye-bye to winter's Orion. Keep looking up!
How did you like this episode?
Please give us your comments. (Click
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* This week's Sky At A Glance
and Planet Roundup from Sky & Telescope.Starry Night Deluxe was used to produce this episode
of Star Gazer
![[SmilinJack]](jack1sm.jpg)
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