Rømer revisited: A modern estimation of the speed of light from observations of Jupiter’s Galilean satellites

Ole Rømer (1644−1710) is remembered today for establishing, from observations of eclipses of the Galilean satellites of Jupiter, that the velocity of light is finite. This paper describes the use of amateur timings of Galilean eclipses observed during 2012−’14 to recreate Rømer’s work, together with a theoretical investigation of the accuracy of such approaches for estimating the speed of light.

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The brighter comets of 2007

This report describes and analyses the observations of the brighter or more interesting comets discovered or at perihelion during 2007, concentrating on those with visual observations.

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