Getting Ready for Mars

The NASA Spirit and Opportunity rovers continue to explore Mars, transmitting images of a desert world. Is there water? The evidence looks good to planetary geologists. "Follow the water" is a great theme for exploring Mars, and it may lead to evidence of life on Mars. The Mars Reconnaissance Orbiter is on its way, and will transmit back to Earth the highest resolution images yet. SETI Institute scientists are participating in these missions, helping us all to explore Mars. I find it very exciting to virtually cruise this foreign world on board my laptop, and am intrigued by the new data and images that are pouring back to us from Mars.

But, I got started in astronomy by looking at the real night sky, not the Internet. My connections go back to childhood. I remember gazing at the Milky Way and shooting stars, seeing a comet through binoculars, and wondering at Sputnik as it crawled across the sky. I think the sky is alluring, and I'm looking forward to seeing Mars in the sky, not just on my monitor.

It's time for Mars to again dominate the night sky. Every two plus years, Earth catches up and passes by Mars. They orbit the Sun like perpetual slot cars, but Mars always has the longer, slower route around the Sun. The last time we passed by Mars was in 2003 when Mars was as close to Earth as it will be for the next 60,000 years. If somehow you missed seeing Mars then, don't be dismayed. While bright, Mars was low in the sky (for Northern Hemisphere folks) in 2003, yielding blurry seeing. This time around, Mars will 32 degrees higher. This is good news for stargazers staring at the red planet through telescopes. With less atmosphere to look through, the image of Mars will be steadier and sharper.

Over the next three weeks, Mars will appear to grow in size and brightness as Earth catches up with the red planet. On October 30, Mars will appear largest: 20.2 seconds of arc in diameter, more than 3 times larger than just a few months ago in April. On November 7, we actually pass by Mars. In astronomical terms, Mars is in "opposition" on the 7th: it is geometrically opposite the Sun as seen from the Earth. It will rise as the Sun sets. As we pass Mars by, it will gradually appear to shrink in size. If weather blocks your view one night, try another; it will be easily visible for weeks.

Viewing will be good throughout November and into December. Small telescopes can reveal polar caps, and surface details. Beyond the Moon, Mars is the only other body in the solar system where we can easily observe surface features with backyard instruments. If you lack a telescope, check your local newspaper for the amateur astronomy club in your area, or visit the "Sky and Telescope" online directory to find your local club, observatory, science center or planetarium. There are sure to be Mars star parties around the end of October. Let's see, if the star parties are combined with Halloween, imagine how many "Martians" might show up for a look through the telescope, or looking for "Mars" candy...but I'm getting distracted.

If you are bitten by the Mars bug, and want to get more seriously involved in outdoor astronomy, consider joining your local club, or one of the specialized astronomical organizations. This fall the ALPO--Association of Lunar and Planetary Observers--has a Mars observing campaign underway. Already, there is a great collection of photographs and drawings posted online, with more each day at the website for the Mars Section of ALPO hosted at the University of Arizona.

I'll be looking for Mars blazing red in the night sky over the next several weeks, and hope that you be there with me in spirit as we gaze at the red planet.

• The Universal Sky Tour: Mars Madness
• Mars Rovers: Complete Coverage