The elusive little planet Mercury is beginning another apparition as an evening star following its superior conjunction behind the Sun on 2008 JUL 29.  This will be a poor one for northern hemisphere observers due to the sharp angle with which the ecliptic strikes the early evening horizon during late summer and early autumn.  But it will be superb for those in the southern hemisphere.

Mercury will achieve its greatest eastern elongation of 26.9° on SEP 10.  But its greatest altitude at 30 minutes after sunset from Chicagoland will be only 3.2° on AUG 29.  For Sydney, Australia that will be 19.7° on SEP 11.  Mercury will achieve dichotomy (50% illuminated like a Half Moon) on SEP 14.  Before that date it will be gibbous and afterward a crescent.  It will then fall to inferior conjunction between Earth and Sun on OCT 07.

On AUG 15 Mercury, Venus and Saturn will appear in a tight group.  Mercury and Venus will be especially near each other on AUG 20 and then meet again on SEP 12.  Mercury and Mars will conjunct on SEP 06 and again on SEP 22.  Mercury will conjunct Regulus on AUG 09 and Spica on SEP 23.  On SEP 02 Mercury, Venus and Mars will aid New Moon spotters. 

I’ve created two graphics illustrating Mercury’s current evening apparition:  one for northern and one for southern hemisphere observers.  They can be seen at:  http://www.curtrenz.com/astronomical.html

Photos and descriptions of Mercury during its current apparition would be welcome additions to this thread.