Saturday, June 19, 2010

First Quarter Plus One, Aristillus, Autocylus, and Archimedes

If you've been following along at home, you remember last night we looked at some mountains.
Well, we're going back to craters, but first another look at Montes Apenninus(see last night):



Now you can pretty much see it in it's full glory.
Tonight we feature a trio, the three amigos if you will:



They should be pretty easy(or not) to spot if you are viewing at home.
More on this later.
Aristillus(55km) is named after an Alexandrian astronomer, Autocylus(39m) is named after another Greek dude, and Archimedes(83km), well, is named after Archimedes the mathetician guy.
Actually guys like Archimedes, Descartes, Euler, etc., I'd rather not think of them if I don't have to.
Now getting back to whether or not you can see this stuff at home.
I've been trying to name stuff you, the reader, can see at home using simple binoculars.
Okay, maybe not.
I haven't tried it myself but I'll be checking starting tomorrow.
The images, if you haven't been following along at home(shame on you) are taken from the eyepiece of my 70mm(objective lens) refractor at 37X power.
If you got a decent set of binoculars, chances are the objective lenses are around 50mm, if you got really primo binoculars, they are probably 70mm or better.
Resolving power is sort of based on the size of your objective lens. The size of you objective lens also dictates how much light your uh, whatever, gathers.
There's some kind of mathematical formula, probably developed by Archimedes or someone like him, that figures all this stuff out.
Then there's stuff like the atmospheric conditions, ambient light and all that other not so good stuff.
Resolving power is sort of like the smallest stuff you can see.
Magnification also has something to do with it, but not as much as you think.
For instance:



There's are three amigos again.
Please direct your attention to the craters marked A and B.
A is Piazzi Smyth, he was some Brit who was into pyramids. Piazzi Smyth is like 12.8km wide and B, Kirch, is like 11.7km wide.
Kirch by the way was a German who discovered a comet in 1680.
I would say that those two features are at the end of the resolving power of my scope.
Anything smaller wouldn't be worth looking at.
Okay, it could probably be a little smaller if the light was good and conditions were right, but not too much smaller.
The smallest stuff I'm looking at is about 7 miles across.
Seven.
Miles.
Just trying to give you, the reader, an idea of the scale of some of the stuff we're looking at.

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