Photo Tips: Mars Is Ready For Its Close-Up—Are You?

John Roach
for National Geographic News

Updated August 27, 2003

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Stargazers in a frenzy by the spectacle of Mars' closest approach to Earth in nearly 60,000 years Wednesday may be compelled to snap a photo of the once-in-a-lifetime phenomenon. They'll need some patience and a little luck.

"The big challenge is that we are viewing Mars through the Earth's turbulent air, and you have to wait for moments when the air is steady," said Michael Covington, an Athens, Georgia-based author of several books on amateur astronomy, including Astrophotography for the Amateur and Celestial Objects for Modern Telescopes.

"This is why photographs are usually much worse than the visual view through the same telescope," he added. "The eye can pick the best moments; the camera doesn't."

Mars mania peaks Wednesday. The red planet will be 4,000 times as bright as the faintest star the eye can see, but astronomers caution that it will still be only as big as a U.S. quarter coin seen from 650 feet (200 meters) away. That means it will look like a bright star in the sky, or a tiny disc, even in a telescope.

For the determined photographer, Covington says the easiest thing is to aim a digital camera through the eyepiece of a telescope—preferably with an attachment—and take dozens of images at different exposure speeds with the camera lens wide open. The bad pictures can be deleted, keeping only the good ones—if any—without wasting film.

"Don't worry that the image is small, planet images always are," he said. The images will show shadings of different kinds of sand, but features such as craters are not visible from Earth-based telescopes. As well, he added, large channels on the Martian surface first observed in 1876 were later proved to be an optical illusion.

Close Up Images

For those lacking the patience or equipment to make their own photographs of Mars, which will be 34,646,418 miles (55,758,006 kilometers) away on Wednesday, images of the close approach taken by the Hubble Space Telescope will be available for download at the website of the Greenbelt, Maryland-based Space Telescope Science Institute.

Hubble orbits about 370 miles (600 kilometers) above Earth and thus is free of the clouds and atmospheric distortion that can plague ground-based telescopes. The Space Telescope Science Institute said in a statement that the images of Mars taken by Hubble will be the sharpest ever and will reveal details as small as 17 miles (24 kilometers) across.

If the Hubble images only ratchet Mars mania up a notch, don't fret. NASA announced August 20 that amateur and professional enthusiasts are invited to suggest locations on the red planet for the Mars Global Surveyor to image with its high-resolution Mars Orbiter Camera.

If the area has not yet been photographed—only 3 percent of the planet has been imaged—Malin Space Science Systems, the San Diego, California-based company that operates the camera for NASA, will put the image request into the database, said Ken Edgett, a staff scientist. The Mars Global Surveyor has been in orbit around Mars since 1997.

"Every request, as long as it meets the rules, will be put into our database…then we just wait until some time in the future when the predicted ground track goes over the location, we can try to take the picture," said Edgett.

The spacecraft's camera has taken more than 120,000 pictures of Mars, many at a resolution sharp enough to show features as small as a school bus. The spacecraft is in good condition and its operation is funded at least through September 2004.

Depending on where Mars is in relation to Earth—think of the two planets as two racecars on separate tracks, one inside of the other, and going at different speeds—the camera can relay 20 to 100 high-resolution images to Earth per day.

Currently the two planets are as close as they get and thus the data rate is at its highest. A year from now the planets will be farther apart, meaning it will take longer for the data to go from Mars to Earth, explained Edgett. As a result, fewer images per day can be obtained.

"Over the course of a year, I would expect to see several hundred [requested photos] get taken," said Edgett. "I think people will be pleased."

Images of the red planet taken by the Mars Orbiter Camera are the basis of several recent discoveries, including pictures that show outcrops of sedimentary rock that may have been deposited in a water-like environment and images of gullies that appear to some scientists to suggest relatively recent flow of liquid on the Martian surface.

The discovery of potential water in the past—perhaps recent past—on Mars raised the possibility that life once existed and may still persist on the planet. Water is considered a key ingredient for life as it is known on Earth.

"We are certain to have plenty more discoveries as time goes on, maybe some from these public targets, who knows," said Edgett, who added that the timing of allowing the public to participate in selecting targets for the Mars Orbiter Camera and the close-approach event is a coincidence.

Mars Opposition

Astronomers explain that while Mars will be as big as it gets as seen from Earth on Wednesday, it gets nearly as big in the night sky every 26 months when Earth laps Mars on its orbit around the sun. Since neither of the planets' orbits are perfect circles, some passes are closer than others.

In 1988 Mars came almost as close and the two planets will again be cozy in October 2005. Mars will continue to appear rather big in the sky for the next month, providing amateur photographers ample opportunity to experiment with making images. For Northern Hemisphere viewers, the 2005 opposition may be even better than this year's.

"At closest approach in 2005 Mars will be 25 percent further away than this year, making it look only 80 percent as big in the telescope. But we in the United States may get a better view of it because at the time Mars will be much further north and higher in the sky," said Covington. "Right now the Australians are having all the fun."