Astronomy dictionary – W
Browse through our astronomy dictionary to find definitions for some of the most common terms used in practical astronomy and space science.
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When the phase (illumination) of a planet or moon’s disc is decreasing in size. For example: ‘A waning crescent Moon can be seen tonight’.
Phases of the lunar cycle when the face of the Moon appears to be getting larger each day. In the waning parts of the lunar cycle, the face of the Moon appears to be getting smaller.
A small and dense type of star formed at the end of a star’s life if it has a mass less than the Chandrasekhar limit, which is about 3 x 10^30 kg.