Jupiter in 2021, Report no.3: Mutual phenomena of the satellites

In 2021, the Jupiter system was edge-on to the Earth and Sun, so the Galilean satellites sometimes eclipsed and occulted one another in “mutual phenomena” (or, in French, PheMus for “phenomenes mutuels”).  Here are  observational records of some of them.  The animations are not all clearly labelled but they are by Andy Casely, Clyde Foster, Phil Miles, & Anthony Wesley (although Wesley’s animations may not play on this web page, for unknown reason).

A specially remarkable series of events occurred on 2021 Aug.15, as Ganymede eclipsed and occulted Europa while both were in transit over Jupiter, while Io and Callisto passed behind and in front of Jupiter respectively.  Superb records of this event are shown on a sub-directory (link below, or via: https://britastro.org/node/26351)  Chris Go also posted a long video of his *live* captures which is linked from our Facebook page.

More systematic collections of these observations are presented by:

     Marc Delcroix:   http://www.astrosurf.com/planetessaf/occultations/images/phemus/index.php?lang=en

     ALPO_Japan:    http://alpo-j.sakura.ne.jp/Latest/Special.htm


  • Dance of the moons on 2021 August 15
  • The British Astronomical Association supports amateur astronomers around the UK and the rest of the world. Find out more about the BAA or join us.