Analysis of lunar crater timings, 1842-2011
2014 September 18
Crater timings are made during a total or partial lunar eclipse as the Moon slowly glides through the Earth’s central shadow cone, or umbra. We have gathered 22,539 observations made at 94 lunar eclipses since 1842 – the largest collection of crater and contact timings ever compiled. In this paper we analyse these timings to derive an improved characterisation of the umbra’s size, shape, and stability over time.