Dan [Turner] [offline and in Utah Astro], Thanks for letting me use your 16" DOB at last night's urban star party. Most of the interesting features on the Moon are organized around impact basins. http://members.csolutions.net/fisherka/astronote/Structure/moongeo/MoonGeolo... Once you understand the relationship between the basins and strucutral features, finding feature feature types is straight-forward. http://members.csolutions.net/fisherka/astronote/Structure/moongeo/MoonGeolo... For example, we were looking at Gassendi last night, a floor-fractured crater on the edge of Mare Humorum that, like many floor fractured craters are tilted towards the center of the mare. We also looked at Rima Hippalus, a series of parallel fractures tangent to the east side of Humorum that related to the basin's formation. Gassendi http://www.lpod.org/archive/archive/2004/01/LPOD-2004-01-15.htm Rima Hippalus http://www.lpod.org/?m=20060421 - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net