Mars still shines at just about the biggest and brightest until 2014. This week also offers some additional, special Martian sights.
The colors of Sirius and Mars: The moon rises and sets later each night this week, allowing Mars and the bright stars of winter to shine in a darker sky. Mars still glows almost as bright as the most brilliant star of any season, Sirius, which is in the southeast, well to the right of Mars in the hours just after nightfall.
I have noted here before that you can tell Mars and Sirius apart by the steady shining of the planet and the strong twinkling of the star. I have also mentioned the color difference between them, calling Mars "campfire-colored," "tiger-colored," or "pumpkin-colored."
NASA's Dr. Tony Phillips, who writes many of the stories for the superb website spaceweather.com, recently came up with wonderful, vivid new descriptions of their hues. Sirius, he writes, shines with the intense blue of an acetylene-torch flame, while Mars burns with the golden-orange of a lit match's fire. Is he right? See what you think.
Mars moves past the Beehive star cluster: Have you ever experienced the illusion that a car you were passing was moving backwards as seen against a distant background of trees? The same illusion is responsible for making Mars seem as if it is moving slowly backward to the west, relative to the distant background of stars. It happens when Earth is passing Mars in their race around their orbits - something that is occurring right now.
Mars, which crept east past the famous Beehive star cluster back around Halloween, now, at full brightness, creeps back west past the cluster. If you are far from city lights, your naked eye can see the Beehive Cluster, in the constellation Cancer, as a fuzzy patch of light to the lower right of Mars in early evening. But most people will need binoculars to view the cluster clearly - and see its sparkling individual stars. Mars is due north of the cluster this Friday but they are close all week. And Mars will make one more pass of the Beehive in April, after its apparent backward, or "retrograde," motion has ended.
Disks of color around the moon: At the Rowan University open house last week, about 200 people got to look at Mars and the moon through telescopes. But when thin clouds moved in, all of the attendees also got to witness a bonus, beautiful sight: Around the moon, we saw a cloud corona, or a disk of green-blue, bordered by a vivid band of red.
This phenomenon occurs when tiny water droplets (sometimes ice crystals) in clouds are all of uniform size. The droplets are similar in size to wavelengths of light and selectively block or reinforce at different angular distances from the moon the blue and red wavelengths that make up moonlight.
This cloud corona was remarkable. At times, it was not circular but elliptical. At other times, there were two sets of blue-then-red, and then more blue with maybe dim red at the outermost layer to make nearly three rings of corona.
Fred Schaaf is a local author and astronomer. He can be reached at: