Mercury as Summer Evening Star

Panorama of the western sky with Mercury and the Moon as seen from Chicago 30 minutes after sunset from 2018 JUN 10 to JUL 27 - See article below.

Mercury - Elongations & Altitudes - 2018

The planet’s elongations from the Sun and altitudes above the horizon as viewed from latitude N 42°

Mercury 02 Mercury 03 Mercury 04


Elusive Mercury is presenting its apparition in the western sky after sunset following its superior conjunction behind the Sun on 2018 JUN 05. This should be a moderately good apparition for observers north of the tropics, and should be an exceptionally fine one for those further south.

    By the standard of 30 after sunset for Chicago, Mercury will reach its highest altitude of  9.6° on 2018 JUL 02. Through a telescope on JUL 07, it will be seen in dichotomy, i.e. 50% illuminated like a Half Moon. Prior to that it will appear gibbous and afterward as a crescent. On JUL 11, Mercury will attain its Greatest Eastern Elongation of 26.4°. It will begin apparent retrograde motion in right ascension on 2018 JUL 24. While decreasing in brilliance, Mercury will fall to inferior conjunction between Earth and Sun on AUG 08.

  Mercury will appear near bright  stars on the following dates: Castor 2018 JUN 22, Pollux JUN 24 & Regulus JUL 24. During this apparition it will not appear near any other bright planets.

 The Moon will appear near Mercury on 2018 JUL 14 without an occultation.

NOTE: Event dates in this article are for North American Central Time at those moments nearest to 30 after sunset for Chicago.

Mercury Angular Diameter - 2018

Graph of the apparent angular diameter of Mercury measured in arcseconds  -  Distance in AU = 6.68 / angular diameter

Mercury Illumination Phase - 2018

Graph of the percentage of Mercury’s apparent disk illuminated

Mercury Stellar Magnitude - 2018

Graph of the brightness of Mercury measured in stellar magnitude

Mercury 05


© Curt Renz

Mercury 01

Mercury Transits Sun - 2019 NOV 11

Previews of the apparent path of Mercury across the Sun Geocentric view and as seen from various cities

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