Observing Highlights for August: Twice Is a Blue Moon
The saying "once in a blue moon" is meant to represent something of rare occurrence. A blue moon is commonly thought of as the second full moon in one calendar month, and August's first full moon occurs on August 1 at 8:27 p.m. Pacific Time, meaning that 29.5 days later another full moon will occur in August, on the 31st at 6:58 a.m. PDT. The next blue moon will not occur until July 2015.
Blue moons aren't named for their color. The moon will look like any other full moon on August 31. But on occasion the moon can take on different hues due to particles in our atmosphere acting as a filter. Smoke from forest fires and ash from volcanoes have been known to produce darker moons, sometimes with a blue or purplish tinge.
The planets put on a good show in August regardless of whether you are a morning person or a night owl. In the early morning hours before sunrise, the brilliant Venus and Jupiter can be spotted in the east. Watch on August 11 through 14 when the crescent moon moves toward and then through the planetary pairing.
In the evening, Mars has been closing in on Saturn, which is hanging out with the star Spica in the constellation Virgo. On August 13, those three points of light will appear to line up, with Saturn above Mars above Spica. If it’s cloudy that night, August 21 will also provide a pretty view as the trio, stretching into a triangular configuration, is joined by the moon.
A new Mars rover named Curiosity is expected to land on the surface of the Red Planet around 10:30 pm PDT on August 5. If all goes as planned, the rover will begin exploring Gale Crater as it looks for water and past or present evidence of microbial life.
If you already know how to find the Summer Triangle, the large figure starting overhead with the star Vega and extending northeast to Deneb and southeast to Altair, look below the triangle to find the little kite-shaped constellation known as Delphinus the Dolphin.
Besides being one of the more charming constellations, Delphinus is also home to some interestingly named objects. The box-shaped portion of the constellation bears the name of Job's Coffin. Within this quartet of stars, the two brightest stars, on the top and bottom of the right side, are named Sualocin and Rotanev, respectively. In 1814, a sneaky man who drew the Palermo Star Catalog hid his name among the stars. That man’s name was Nicolaus Venator, and his first and last names spelled backwards make Delphinus’s star names of Sualocin and Rotanev.
Photo: The second full moon in August will be a Blue Moon. Credit: Håvard Kristoffersen.
Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.