suitti (suitti) wrote,

Mars, Bigger than the Moon

It's that time of year again. It's August 27th. And the email from 2003 has been modified and recycled again. Each time, it gets less factual. I didn't get a copy this year. But you can get the gist of it here.

In 2003, the claim was... in a 75x telescope, Mars appears the size of the Full Moon (naked eye). That wasn't a hoax. It was handy. Can you see the "Dog on the Moon" or other shapes in the maria? That's about the level of detail you might have expected on Mars in 2003 in a back yard scope.

Back then, i did the math. The Moon had about 71 times the apparent size of Mars. The Moon is so bright, you think it's bigger. It's not so big. It's about 30 arc minutes across. Your eye can resolve about 3 arc minutes. So the Moon is only something like 10 pixels across. That is, it's a little tiny icon image. Can you see any craters on the Moon, naked eye? I tried to do some image manipulation to give you an idea what a 10x10 pixel Mars looks like. But it's very small on your screen. So instead, i then took that small image and made it bigger. In my opinion, Mars looks better at 100x through a scope.

Now is the time to mention that though Mars won't be at opposition in late August this year, it will be at opposition in January 2010. It's not that long from now. And, it won't appear as large as in 2003. So you'll need maybe 120x instead of 70x to get the icon resolution. But a well collimated ten inch scope will easily support over 240x. Your local astronomy club has several scopes this size or larger. And, they'd be happy to show you Mars in January for free at one of their monthly star parties. Dress warm!
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