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An Improved Oblateness for the Earth’s Thermosphere from Lunar Eclipse Observations
Published online by Cambridge University Press: 25 April 2016
Abstract
The current ephemerides include an allowance for umbral oblateness based on the flattening of the Earth’s geodetic reference spheroid; there are few published estimates for umbral oblateness derived directly from the geometry of a lunar eclipse. This paper reports umbral oblateness values which have been derived from 7,400 crater contact timing observations of twenty-one lunar eclipses by amateur and professional astronomers since 1972. The observed umbral oblateness was found to be typically three times the geodetic reference spheroid flattening.
- Type
- Solar and Solar System
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- Copyright
- Copyright © Astronomical Society of Australia 1992
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