The Night Sky Guy

Pegasus: A Celestial Landmark of Fall

This time of the year mother nature is changing all around us – temperatures are getting colder, brisk winds abound and the leaves have mostly fallen. The night skies too are transitioning from summer to winter and there is one gigantic constellation that is the celestial landmark of autumn.

Emblazoned across the evening overhead sky is Pegasus, the ancient constellation representing the mythical winged steed. From the light polluted suburbs you will easily find the chest area of Pegasus marked out by four stars forming a giant square, known as the Great Square of Pegasus. To track it down simply face the southeastern evening sky all season long.

Pegasus is the seventh largest constellation in the entire sky which could swallow up more than 30 full Moons side by side. Though each corner star of the square is only moderately bright, they’re relatively easy to locate because there are no stars in this area of the sky that compare.

Easy Deep Sky Treasures

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Lying roughly halfway, just outside the line between the top and right corner stars is the very ordinary looking star 51 Pegasi. On October 6, 1995 this faint star took center stage with the incredible announcement that it was wobbling like a top in space. Astronomers observing 51 Pegasi suspected that something was tugging at it; not a star but a planet. The companion to 51 Pegasi was the first alien planet discovered orbiting a normal, Sun-like star. Probably half the mass of Jupiter the planet orbits 51 Pegasi so close that its year lasts only about 4 days!

Don’t expect to see this exotic world though, not even the Hubble Space Telescope can directly catch a glimpse; It’s just too far away from us and too close to its parent stars glare. From a dark site try your hand at hunting down this historical star with the naked eye or maybe using binoculars from your own West Island backyard. Either way, it’s amazing to think that this fraternal twin of the sun, over 55 light years out, marks the home of a strange alien world.

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Using binoculars or from a dark site you should be able to make out much of the rest of the constellation. The mythical figure of the horse is upside down for observers so the shoulders and head of the horse trails down from the bottom right corner star of the Great Square. Look carefully with a pair of binoculars at the star representing the flying horse’s nose and  you will find a fuzzy ‘fly’ sitting on it. Known as M15 this is a giant swarm of stars called a globular cluster. A round ball of hundreds of thousands of star shining at about magnitdue 6.3 it is just at the limit of naked eye visibility from a very dark location, but a small telecope from your city backyard will begin to reveal some of its members at the outer edges. M15 lies about 30,000 light years from Earth.

Space News Extra: NASA’s Cassini spacecraft that has been orbiting the Saturn system flew through a giant geyser originating from the the icy Moon Enceladus this past Monday. At its closest point the probe plunged just 100 km above the moon surface. Experts believe the plume, which shot up to 400 km into space is composed of water ice and is peppered with organic molecules. Many believe that there may be a large ocean hidden underneath a thick layer of ice covering Enceladus. For complete coverage of the Nov.2 flyby and the latest images being beamed back from Cassini click here.

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