November 16, 2013
image by Leo Alerts, Belgium
Recently LPOD compared the north polar region crater Pythagoras to Copernicus in that both are large complex craters with terraces, central peaks and mostly flat floors. Like Pythagoras, Moretus, near the south pole, is older than Copernicus, based on its lack of a ray system. Comparison of the LRO QuickView images of the two craters (both at a resolution of 125 m) shows that Moretus has more small craters on its floor than does Pythagoras suggesting that the southern crater is older. Like it opposite pole cousin, Moretus originally had a floor veneered with impact melt but over time is was gardened, maybe rototilled, by random impacts so that the flatness remains but the impact surface texture is gone. Oh, if only we had been observing a billion years ago when the two polar craters were fresh with streaming rays, and Copernicus might still be hot with incandescent melt lighting up its floor. Tycho, was still 900 m.y. in the future.
Nov 14, 2013. Celestron 14 + dispersion corrector + redfilter + 1.8x barlow + DMK21AU618 webcam.
21st Century Atlas charts 15 & L4
Yesterday's LPOD: Hot And Cold Basins
Tomorrow's LPOD: Flooded Old Craters