Bad Astronomy

Leonids ROCK!

So you didn’t see too many Leonids last week, didja? Too bad; me neither. But some locations worked out pretty well.

Like Arizona, at Kitt Peak observatory Mt. Hopkins. They have very dark skies there, and lots of telescopes. They also have an all-sky camera; a fisheye lens hooked up to a sensitive camera that points straight up. On November 19 it caught lots of meteors, and as you can see in the downloadable video.

This video rocks.

Things to note:

1) You don’t really start seeing meteors in the video until after local midnight. That’s because that’s when the part of the Earth you’re standing on is facing into the direction the Earth itself is headed into space. Sound weird? Think of it this way: when driving in the rain, the rain hits the front windshield but very little hits the back. You get hit with more rain if you face forward, into the direction the car is headed. Same thing with the Earth. I really need to draw this up someday since I wind up explaining it so much. :)

2) At about 02:51, the screen flashes with a really bright meteor. Then, in the lower right part of the frame, you’ll see that it left a spectacular trail. The upper atmospheric winds twist it all up, and it takes a full hour to blow across the sky, all of which is in the video. Amazing.

3) There’s another one at about 05:30, but not as bright and persistent as the earlier one.

4) This is cool: meteors appear to radiate away from a point in the sky, which has to do with the way the Earth’s orbit intersects theirs. The Leonids appear to come from Leo (hence their name), which, in the video, is near the top of the screen. The Taurids are another meteor shower that come from the direction of, duh, Taurus, which is near the bottom (just above and to the right of Orion). That shower peaks around the same time as the Leonids, and you can see meteors from both showers in the video. You can easily see the difference between the two because the Leonids move top to bottom, and the Taurids move right to left. Note that the Leonids tend to zip across the sky much faster than the Taurids do! That’s because we are smacking into the Leonids head-on, and the Earth’s orbital speed adds to the Leonids. The Taurids come in from the side, so to speak, and so they appear to move much more slowly.

Very cool.

Tip o’ the dew shield to friend and BABloggee Adria Updike.