Moon Glides by Bright Star, Mars Next Week Before Dawn

July 22, 2011

AUSTIN, Texas — The moon puts on a great show before dawn next week as it passes by a bright star and planet, according to the editors of StarDate magazine.

The moon stands closest to Aldebaran, the bright star known as the eye of Taurus, the bull, an hour before dawn on Tuesday, July 26 in the eastern sky. The moon shines next to Mars in the east at the same time the following morning. Both Mars and Aldebaran glow orange, but right now Aldebaran is about twice as bright as Mars.

High-resolution images and high-definition animation that show the changing positions of these celestial sights over several days are available online at StarDate’s Media Center. There, you can also sign up to receive advanced e-mail notices of future skywatching events.

The animation is also available on StarDate's YouTube channel.

Color is a rare commodity in the night sky. The sky itself is black, most of the stars are white, and the Moon is painted in shades of white, black and gray.

Like a neon bulb, Aldebaran produces its own color. Cooler stars shine redder than hotter ones, and Aldebaran's surface is thousands of degrees cooler than the surface of the sun. Other prominent reddish-orange stars include Antares (whose name means "rival of Mars"), which puts in its best show during July and August evenings, and Betelgeuse, in Orion, which highlights the winter sky.

Mars doesn't generate any light on its own. Instead, like the moon, it shines by reflecting sunlight. The light strikes a surface that is painted in varying shades of orange, yellow, gray and black. Most of the orange and yellow are produced by fine-grained dust that contains a lot of iron oxide, better known as rust.

As Mars grows brighter later in the year, its color will appear to grow more intense. By year's end, you'll see why it is called the "Red Planet," as Mars provides on of the most vivid spots of color in the night sky.

Published bi-monthly by The University of Texas at Austin McDonald Observatory, StarDate magazine provides readers with skywatching tips, skymaps, beautiful astronomical photos, astronomy news and features, and a 32-page Sky Almanac each January.

For more information, contact: Rebecca Johnson, McDonald Observatory, College of Natural Sciences, 512 475 6763.