Astronomy Activity - Tycho's Rays

[Ad Astra]

Hi Folks,

I had about 65 kids out on the football pitch with 150mm dobs last night trying this one! We were observing the rays of the giant crater Tycho, sketching the ray system - then using some simple ratio and proportion math to calculate the length of the rays - some of them are really huge!!

The activity went very well, and you can try it if you can get out in the next night or two when the moon is nearly full and the rays are easily visible.

For the more mathematically inclined, you can try to use your sketch and a lunar atlas to locate the latitude / longitude of each end of the ray, then do a little spherical trigonometry to find the actual length of the ray as it curves across the lunar surface. (The method in the lab assumes that the lunar surface is 'flat'...) There isn't much difference between the two methods for shorter rays, but it can be subtantial differences for longer rays!

Have fun!

Dan

Lab #11 - Tycho's Rays.doc