Scorpius sign summertime is really here

Thursday, July 23, 2009

Ah, summer is truly here! High temperatures, afternoon thunderstorms that clear the sky of dust, and Scorpius, the Scorpion is high in the south.

One of the most prominent constellations in the night sky, Scorpius is one of the 12 zodiacal constellations that circle the ecliptic, the path the sun follows in the sky.

The stars marking the head of the scorpion are due south in the early evening at about 9 p.m. MDT. That is when our old friend Leo the Lion is diving below the western horizon taking our other old friend, Saturn, with him.

Scorpius is one of the few constellations to actually resemble its namesake, a scorpion. The three second- magnitude stars marking the head are due south and the remainder of the body stretches down and to the left, curving around to make a fish hook shape.

From our location here in southwest Nebraska, Scorpius is very low on the southern horizon and sometimes the bottom of the hook and the two stars marking its "sting," are not visible. For our friends south of the equator in Australia and New Zealand, however, this pair passes high overhead.

Those two stars, often called the "Eyes of the Cat" in some astronomical circles, give the appearance of a double star but such is not the case. This is another instance where stars appearing close together are really far apart. Such a pairing is called an optical double.

The brightest of the pair, second magnitude Shaula, is approximately 709 light years away while third magnitude Lesath, on the right, lies a closer 522 light years. However, Shaula itself is a double star.

To find the claws of the scorpion you will have to look up and to the right of the beast. The two stars marking the claws were moved on some early sky maps to make the constellation Libra, the Scales. Look just to the right for two almost third magnitude stars with tongue twister names.

The northern of the pair is called "Zubeneschamali," the Northern Claw, and the other is "Zubenelgenubi," the Southern Claw. Say those three times real fast.

Another marker of the Scorpion is the bright red star at its heart, Antares, the Rival of Mars. Antares is a red giant star about 700 times the size of our sun. If it were located where our sun is, the surface of the giant would reach out to somewhere near Jupiter.

Another red giant star to rival Antares is Betelgeuse, the right shoulder star of Orion, the Hunter. In ancient mythology Orion boasted he could slay any beast. That is when the gods sent the scorpion to gave him a poisonous sting in his heel which killed him. The gods then place both of them in the sky. But, they were placed so that neither one appears in the sky at the same time. When one is rising, the other is setting.

SKY WATCH: First quarter moon, July 28. Wednesday, July 22, there was a total eclipse of the sun. However, if you didn't live in China, India, or the South Pacific you didn't see it. Saturn is leaving the evening sky for its trip around to the far side of the sun. Bright Jupiter is the brilliant object rising in the east at about 11 p.m. MDT. It will be high in the south at about 3 a.m. Use your binoculars to find faint Neptune. It is about one degree directly above the King of the Planets, but don't mistake it for the faint, seventh magnitude star Mu Capracorni just above and left of Jupiter and right and below Neptune. If you are an early riser, look in the east between 4 and 4:30 a.m. MDT for a very bright Venus. Use your binoculars again to look for a much dimmer Mars. The red planet will be located about half way between Venus and the Pleiades star cluster which is up and to the right.

NEXT TIME: Scorpius part two and more astronomical blathering.

Respond to this story

Posting a comment requires free registration: