Thursday, February 07, 2008

Dr. Vector visits the other Tethys

Usually when paleontologists talk about Tethys, they mean the ocean. Which is gone, or at least busted up pretty good. But tonight I explored the other Tethys for the first time, if "explored" is not too grand a word for sighting a wee dot of light at the edge of visibility at 125x in my telescope. Tethys is the fifth-largest of Saturn's 60-odd moons. It's about a thousand kilometers in diameter, slightly less than the distance between Berkeley and Salt Lake City on I-80 (a drive that figures prominently in John McPhee's Basin and Range and Assembling California, and in my own personal history).

I also saw Titan--biggest moon in the solar system, larger than the planet Mercury--and Iapetus. Dione and Rhea were too dim and too close to the planet to make out. (I don't know which moons those are in the photo above, I just liked it and didn't feel bad about ripping it from the horoscope site where Google Image Search found it.)

Actually I had no idea which moons I was seeing at the time; I sketched Saturn and the three I could see and did the IDing later, using Stellarium (still free, still awesome). Here's a screencap:

Seriously: if you haven't seen the rings of Saturn, or the moons of Jupiter, or the Orion Nebula, or the Double Cluster, with your own eyes, you owe it yourself to start figuring out how to make that happen. If you don't have a telescope, find a friend who does. Or buy one; Orion has some good 'uns for less than you think (my six-inch Dob*, which looks like a freakin' cannon, was under $300 nicely equipped). Or if you're not too far, invite yourself over and look through mine. The views don't suck.

* One of the ironies of amateur astronomy is that, thanks the success of even larger Dobs, a telescope four feet long, seven inches in diameter, and weighing 35 lbs is considered small.

Yes, it's true, you can Google up some Hubble images that will smoke anything you can see through a backyard telescope. Nothing wrong with that--I've got a big fat book on the shelf next to me with unreasonably gorgeous views of everything from the moon on out to the galaxy swarm in the Hubble Ultra Deep Field. But I promise you this: your first eyeball view of Saturn or Jupiter or whatever gem the scope is pointed at will sock you in the brainpan in a whole different way. Try it and see.

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