November 14, 2008
image by Bart Declercq, Haaltert, Belgium
Janssen is a peculiar crater. It is large and made up of multiple craters so we can't easily interpret its shape and history. But with a diameter of about 200 km it is about the size of larger mosaic by Bart gives the evidence for the possibility - do you see it? The major diagnostic feature of basins is indicated by their full name: multi-ring impact basins. To the left of Janssen's rim is the arc of a low ridge, is this an outer basin rim? Unfortunately, this ridge is not detected around other sides of Janssen. So is this all that is left of a perhaps partial outer basin ring, or is it not a ring at all, but merely a random ridge? I don't know.
Sept 19, 2008, 2h50m UT. C9.25 @ F/20 + DMK31AF @ 30 fps + Astronomik red filter
Rükl plates 67 & 68
Yesterday's LPOD: Snapshot Map
Tomorrow's LPOD: Indian Close-Up