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optical oblateness
paxi-ye nuri
Fr.: aplatissement optique
(polar flattening) The ratio of the difference between equatorial and polar diameters to the equatorial diameter. A sphere has an oblateness of 0; an infinitely thin disk has an oblateness of 1 (Ellis et al., 2007, Planetary Ring Systems, Springer). See also: → optical; → oblateness. |