selenelion

English

Alternative forms

• selenehelion

Etymology

French coinage, from the Ancient Greek σελήνη (selḗnē, “moon”) and ἥλιος (hḗlios, “sun”).

Noun

selenelion (plural selenelions)

1. A lunar eclipse occurring as the moon sets, simultaneously with sunrise.
   • 2001, Paul Davies, Duncan Steel, Eclipse: The Celestial Phenomenon That Changed the Course of History (Joseph Henry Press) p. 57

     This phenomenon is called a "horizontal eclipse" or, from a French term, "selenelion." ... In modern times, the first record seems to date from 1590, when the great astronomer Tycho Brahe saw a selenelion from his observatory ....

   • 2007, William Poole, "Antoine-François Payen, the 1666 Selenelion, and a Rediscovered Letter to Robert Hooke", Notes and Records of the Royal Society of London, Vol. 61, No. 3 (Sep. 22, 2007), pp. 251-263 JSTOR

     This he immediately published, under the title Selenelion ou Apparition Luni-Solaire .... The coinage ‘selenelion’ was his own .... Payen asserted that refraction on its own could not account for a selenelion...

   • 2010 June 26, Kelly Beatty, “In Search of Selenelion”, in Sky & Telescope:

     I decided to watch for an uncommon eclipse phenomenon known as selenelion, seeing the Sun near the horizon and the eclipsed Moon near the opposite horizon at the same time.

   • 2014, Joe Rao, Total Lunar Eclipse On Wednesday Will Be a Rare 'Selenelion'‎^[1]:

     On Oct. 8, Interested skywatchers should attempt to see the total eclipse of the moon and the rising sun simultaneously. The little-used name for this effect is called a "selenelion," a phenomenon that celestial geometry says cannot happen.

   • 2014 October, Alan MacRobert, “Eclipse of a Large Moon”, in Sky & Telescope, page 52:

     Meteorologist Joe Rao points out that this eclipse presents an unusual chance to try seeing a selenelion: when the Sun and eclipsed Moon are both above the horizon at once.

Synonyms

• horizontal eclipse