Keywords: Venus Black Drop effect.png en The black drop effect as depicted by Torbern Bergman Philosophical Transactions 52 part 1 1761 227 “228 reproduced in Kragh H The Moon that Wasn't The Saga of Venus' Spurious Satellite Birkhäuser 2008 P 41 Torbern Bergman 1761 PD-old-100 1761 Transit of Venus Black drop effect |