Script for 'The Night Sky in March', 1960-03
Scope and Contents
Two copies of Porter's script for 'The Night Sky in March' on stellar colours, Betelgeuse and Aldebaran being red stars, and Sirius, Arcturus and Vega being instantly recognisable by colour; Jupiter and Saturn (easily identified because of their steady lights) being found in the south-east before dawn; the similarities in the colours of the stars in Orion's belt, the difference between Castor and Pollux, close double stars sometimes giving contrasting colours and the numbers of double stars in the sky, greater than can be attributed to chance alignment; the recognition of systems under mutual gravitational attraction by William Herschel, who showed by observation that they actually revolve about one another; Herschel's work having started as an attempt to measure stellar distances, but shifting in emphasis to binary systems; orbit measurements yielding mass and separation of the systems, the limits to measurable separation using optical telescopes, spectroscopic double stars and eclipsing binaries; hundreds of orbits having now been calculated; half the stars in the vicinity of the Sun being double or multiple systems, a proportion probably holding for the rest of the universe; the varying separations of binaries, varying star sizes and periods of revolution, tides on close binary stars and the cases of Capella, Sirius and Procyon; and multiple systems, such as Proxima and Alpha Centauri, with a huge orbital period, the Castor system of three binaries and the formation of binary systems. The second copy of the script is annotated.
- Creation: 1960-03
- From the Series: Porter, John Guy, 1900 - 1981 (astronomer) (Person)
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