BAA electronic bulletin No. 00415 -- http://www.britastro.org/
The 2009 apparition of Jupiter is under way and observers in Australia are already sending excellent images.
A special aspect of this apparition is that the galilean moons are performing mutual occultations and eclipses, since we passed through Jupiter's equatorial plane on April 19. These events are fascinating to watch, and as imaging has improved so much in the 6 years since they last occurred, we now have a great opportunity for imaging them. Indeed Anthony Wesley (Australia) has already produced an unprecedented movie showing Europa passing in front of Ganymede:
http://www.acquerra.com.au/astro/gallery/jupiter/20090508-1802/Europa-Ganymede-anim.gif
The times of mutual phenomena are listed in the BAA Handbook, and also on-line in the Astronomical Almanac:
http://asa.usno.navy.mil/SecF/Jupiter.html
Meanwhile the planet itself is very quiet, having settled down after the 2007 upheaval. There are localised bright 'rifts' in the NEB (as last year), but otherwise little atmospheric disturbance. The main question this year is whether the major belts will enter another cycle of grand-scale changes as in 2007, or whether they will revert to 'normal' behaviour as in 1995-2006.
The Great Red Spot is at L2 = 133 (with only weak reddish colour), and oval BA is at L2 = 343 (May 8) (with virtually no reddish colour left).
See the Jupiter Section web site for our observing guide, and for many interim reports from recent years - including a detailed final report on the zonal winds in the 2007 apparition.
John Rogers
BAA Jupiter Section Director
Bulletin transmitted on Tue May 26 12:44:41 BST 2009
(c) 2009 British Astronomical Association