Orpington Astronomical Society

Astronomy => Alerts! Questions? Discussions... => Topic started by: Rick on Oct 01, 2013, 21:25:47

Title: [BAA-ebulletin 00762] Upcoming double and triple events of Jupiter's moons
Post by: Rick on Oct 01, 2013, 21:25:47
[BAA-ebulletin 00762] Upcoming double and triple events of Jupiter's moons
(c) 2013 British Astronomical Association    http://www.britastro.org/

A fascinating series of double and triple phenomena of Jupiter's moons will be occurring throughout October.  The coupled orbits of the inner three moons mean that their phenomena recur at intervals of one week plus a few hours.  The events visible from Europe including the UK are transits of I + II, preceded by their shadows, on Oct.5 (02:38-06:05 UT), Oct.12 (see below), Oct.19 (06:25-09:54 UT), Oct.26 (08:37-11:46 UT). (Times are from the first appearance of two shadows on the disk, to the last appearance of two moons on the disk.)  John Sussenbach has already provided a nice time-lapse movie of the first event in this series, on Sep.27/28.

The best event is on Oct.12, with the shadow of IV in transit along with the shadows of I + III.  There will be at least 2 moons and/or shadows on the disk from 03:24-08:02 UT.

Two other series of similar events will be occurring this month as well, but at times visible from non-European longitudes:

Transits of I + II, preceded by their shadows:
Oct.1, 8, 15, 22, 29/30.

Transits of I + III, preceded by their shadows (with II entering eclipse in the meantime):
Oct.3, 10, 17, 24, 31.

See the BAA Handbook for full details.

John Rogers
(Jupiter Section Director)