MERCURY
EARLY SPRING MORNING APPARITION OF MERCURY
Elusive Mercury will soon commence its poorest morning apparition of the year for observers north of the tropics. This after it moved between Earth and Sun in inferior conjunction on 2012 MAR 21. Late winter and early spring present the least favorable celestial geometry.
Mercury resumed direct movement in right ascension on APR 03. It achieved its greatest altitude for Chicagoland observers at 30 minutes before sunrise of 3.4° on APR 13. Greatest western elongation of 27.5° was achieved on APR 18. On APR 21 the planet will be seen in dichotomy, i.e. 50% illuminated like a Half Moon. Before then it will appear as a crescent and afterward gibbous. While increasing in brightness Mercury will fall to superior conjunction behind the Sun on MAY 27.
During this apparition Mercury will not appear in the vicinity of bright planets or first magnitude stars. However, a slender crescent Moon appeared 7° above Mercury on APR 18.
NOTE: Event dates are for North American Central Time at those moments nearest to 30 minutes before sunrise from Chicagoland.
© Curt Renz
Mercury Illumination Phase -
Graph of the percentage of Mercury’s apparent disk illuminated during 2012
Mercury Stellar Magnitude -
Graph of the brightness of Mercury measured in stellar magnitude during 2012