My Astronomy Class - Lunar Lava Flows

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As we move into the waxing moon this week, we sometimes find ourselves grumbling that the increasing moonlight interferes with our observation of the deep sky. With the waxing moon, we get to see sunrise spread across the face of the lunar globe over the course of the days, and we can take this opportunity to use the low solar angle to reveal amazing geological features across the lunar surface.

We all know that the lunar maria are large impact basins, roughly 3.2 - 4 billion years old, and that after the asteroids punctured the lunar surface, these great basins filled with lava over the millenia. It is still possible today, to see where different lava flows have broken out of their confining basins, where large crater rims have been besieged with lava flooding, and then given way. We can see the ripples and flow marks in the lava on the great basins today. Color also gives a clear indication of where one flow succeeded another. It is often possible to trace the history of an area geologically by looking for which lava flows are on top and which have been buried, overflowed, or otherwise obscured.

For those with a dobsonian or other Alt-Az scope, this lab represents a great challenge. To sketch and to track at the same time with any Alt-Az telescope is very difficult. You will have to limit the maximum magnification in order to have reasonable time to sketch between moves of the telescope.

For those with equitorial mounts, and especially those with telescopes capable of motorized or computerized tracking, this is just the challenge you've been waiting for. A chance to find an interesting target and then to study it without losing it out of the eyepiece. Your sketch can be at a higher magnification and may show fine details such as rilles and flow lines that the non-tracking scope simply cannot show without great difficulty.

I will scan and post a couple nice drawings from my class this semester to show you all what can be accomplished at the eyepiece with a little practice. Comments and questions are always welcome.

Cheers,

Dan

Lab #10 - Lunar Lava Flows.doc