The elusive little planet Mercury has begun its apparition as a morning star following its inferior conjunction between Earth and Sun on 2009 JAN 20. This will be a somewhat challenging apparition for northern hemisphere observers, but will involve fascinating conjunctions with the Moon, Mars and Jupiter.
I’ve created a graphic illustrating Mercury’s morning apparition as viewed from Chicagoland, although it should well serve most northern hemisphere observers. I’ve also assembled an animation video to demonstrate the conjunctions. They can be seen at: http://www.curtrenz.com/astronomical.html
All dates given here are based on CST. Mercury will reach its greatest altitude at 30 minutes before sunrise from Chicagoland on FEB 05 at 7.9°. It will achieve dichotomy (50% illuminated like a Half Moon) on FEB 08. Before that date it will be a crescent and afterward gibbous. The planet will reach its greatest western elongation of 26.1° from the Sun on FEB 13. While increasing in brightness, it will then fall to superior conjunction behind the Sun on MAR 30.
Mercury will appear to pass 4.3° north of Mars on JAN 27. Then a pretty set of conjunctions will be occurring from mid-February through early March. Mars will appear to pass 0.6° south of Jupiter on FEB 17. Late on FEB 23 Mercury will pass 0.6° south of Jupiter. Then Mercury will pass 0.6° south of Mars late on MAR 01. The tightest grouping of the three planets will involve a separation of 3.7° on FEB 23.
The waning crescent Moon will appear to pass near Mars on JAN 24 and near Mercury and Jupiter on JAN 25. Then it will join in the close grouping of those three planets in February. It will pass nearest Mercury and Jupiter on FEB 22 and nearest Mars on FEB 23.
Photos and descriptions of Mercury and its conjunction partners during this morning apparition would be welcome additions to this thread.