The Observation of Lunar Impacts.pdfVIP

48 WGN, the Journal of the IMO 0:0 (0) The Observation of Lunar Impacts Costantino Sigismondi and Giovanni Imponente The intense activity of cratering on the Moon and in the inner regions of the solar system was accomplished during the first 109 years [1]. Occasionally, some impact events occur even nowadays. In Section 1, we treat, from a historical point of view, the Earth-based observation of lunar impacts. In Section 2, we consider the visibility conditions of such events evaluating the luminosity of the background upon which an impact shines. In Section 3, the luminosity of an impact is discussed. The occurrence of lunar impact events outside of meteor shower periods is calculated using the hourly rate of the sporadic meteors and their population index. The evidence of a larger rate of impacts of meteoroids in the past under these hypotheses is presentend in the last section. 0 0 1. Evidence of lunar impacts 0 2 The first important evidence of lunar impacts has been the observation recorded on June 18, n 1178 (Julian calendar), by a few men after sunset and registered in the chronicles of Gervase of u Canterbury [2]. They observed the upper horn of a crescent moon to have split with fire and J sparks emanating from the division point. This report was interpreted to be a description of 5 1 events related to the formation of the lunar crater Giordano Bruno [3]. On November 18 and 19, 1999, several impact events of initial magnitude between +3 and +7 1 v were recorded with a video tape and by naked-eye near the center of the Moon’s dark limb. 0 Those flashes resulted from Leonid impacts on the Moon, because the center of the 1899 dust 1