Planets wandering through the Zodiac

I've been fascinated by the movement of planets through the zodiac lately, showing this to guests at star parties and when I give talks at the California Academy of Sciences. Jupiter, being the dominant planet in the evening sky, brings my attention to the constellation Aries, which from an urban setting is two somewhat-bright stars paired next to blazing Jupiter. Following the ecliptic toward the east, you find a series of beautiful and bright constellations including Taurus, Gemini and Leo. By the time Leo is rising in the late evening, Mars rises with it, a distinctive orange-red color in contrast to the white and blue-white stars of Leo. By early morning when I first look outside, Virgo has risen, and along with it, Saturn.

Jupiter has a wonderful pattern of travel through the zodiac, moving one 'sign' per year as we observe it in its 12-year long journey around the Sun, seeing the slowly changing backdrop of stars along the ecliptic. By stark contrast, Mars flits rapidly from one constellation to the next, out of Leo and into Virgo in the coming weeks. And by contrast in the other way, Saturn lumbers along gradually changing zodiac position every 2 1/2 years, moving from Virgo at present to Libra in 2014.

EarthSky has a nice writeup on seeing all 5 visible planets in January. Enjoy the month and get outside if it's not too cold. As for me, I've been entranced by the clear nights here in San Francisco and look forward to the ongoing winter skies and the bold bright planets that punctuate the view.

Image courtesy Sky and Telescope.