giovedì 26 maggio 2016

Mars

FEAR AND DREAD AROUND MARS: The moons of Mars are so small, some astronomers believe they are captured asteroids. Named Phobos and Deimos (Fear and Dread), the diminutive satellites average 17 km in diameter and are rarely seen in pictures of the Red Planet. On May 24th, astrophotographer Dennis Simmons of Brisbane, Australia, attempted to capture both. Rate of success: 100%.
Mars shines 242,000 times brighter than Phobos and 741,000 times brighter than Deimos. The two moons are easily lost in the glare. "Deimos was relatively easy, but Phobos had to be gently teased out of the data," says Simmons, who used a 9 inch Celestron telescope.
This is a good time for astrophotographers to seek Fear and Dread. Why? Because Mars is unusually close to Earth. On May 30th, the two planets will be only 47 million miles apart--the closest they've been since 2005. This proximity not only boosts the apparent brightness of the tiny moons, but also increases their angular separation from Mars. Browse the gallery for sightings. 

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