Tuesday, May 25, 2010

Kepler and Aristarchus

Well, the old Moon is almost full.
When I say old, I mean old.
Like 4.6 billion years old.
Our solar system is thought to be around 5 billion years old, so the Moon is not quite original equipment.
Anyways, according to Sky and Telescope, we are two days away from full.
So what's so good about a full Moon?
Nothing really, for it's not even a very good time to observe.
As I said the last time though, it is a good time to see those ejecta rays coming from Tycho and Copernicus:

If you've been following along at home, you know that Tycho is the crater on the bottom with large rays and Copernicus is in the middle on the right, with a smaller ejecta field.
If you haven't been following along at home, here you go:

Don't forget these images are mirror reversed.
As you can see, I've added a couple of other things. Plato is a dark spot on the edge of Mare Imbrium(sea of rains) that's about 101km wide. Technically it's called a walled plain.
Moon nomenclature don't you know.
Off the side of Copernicus, you can see Kepler, named after the famous astronomer. The ejecta field is not as large as Copernicus, but still quite visible even with binoculars.
Kepler was a dude who had a theory that the Earth revolved around the Sun. Unfortunately, he couldn't figure out the retrograde motion of the planets so he made up some stuff called epicycles to account for it. Sort of difficult to explain, so I'll let you look it up.
If you are so inclined.
Near the terminator, yes, it's the terminator for the Moon is not quite full, is Aristarchus. He was a Greek astronomer who first came up with the notion that the Earth spun on an axis and revolved around the Sun.
Unfortunately, nobody believed him and it took guys like Copernicus and Kepler to prove him correct.
Now you can really see the rays coming from Tycho.
I'll tell you, I wouldn't have liked to be Moon walking when whatever made that puppy hit the surface. If you look good, you can see rays that extend all the way North.
Okay, so there you go, the almost full Moon.
Hopefully as it wanes, I'll be able to get more pics.
Oh, and your Moon factiod for the night.
Lemme see.
While the same side of the Moon always faces Earth, 59% is actually exposed to us. This is because you get a different view depending on where you are on Earth and because of something called librations. Again sort of difficult to explain without pictures so if you have to know, well, you know what to do.
Happy Moon viewing.
Just don't start howling.


John Romeo Alpha said...

Is that an airplane in the right side of the first picture?

limom said...

No, I think I got a bad pixel or some kind of artifact. Not a problem for regular shooting, but bad for nightime shots. I forgot to PS it out.