2 Responses

  1. Earliest known use (by me, but certainly may
    be predated), soon after the 1976 total solar eclipse.  Also see:
    http://nicmosis.as.arizona.edu:8000/UMBRAPHILLIA.html

  2. DaveGault says:

    Not only solar eclipses but occultations in general!
    When the moon or an asteroid passes in front of a distant star, the moon or asteroid casts a shadow into space and if the earth intercepts the shadow an umbra is created upon the ground. As the shadow sweeps by the observer the star briefly disappears.  A Solar Eclipse is realy a Lunar Occultation, it’s just that the star is up close and personal!

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