for National Geographic News
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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 telescopepreferably with an attachmentand take dozens of images at different exposure speeds with the camera lens wide open. The bad pictures can be deleted, keeping only the good onesif anywithout 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 photographedonly 3 percent of the planet has been imagedMalin 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.
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