Mercury as Winter Morning Star

Panorama of the southeastern sky with Mercury and the Moon as seen from Chicago 30 minutes before sunrise from 2016 DEC 31 to 2017 FEB 14 - See article below.

Mercury - Elongations & Altitudes - 2016-17

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

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Elusive Mercury is presenting it predawn apparition in the southeastern sky following its inferior conjunction between Earth and Sun on 2016 DEC 28. This has been fairly good apparition for observers north of the tropics, and even better for folks further south.

   Apparent direct motion in right ascension resumed on 2017 JAN 08. By the standard of 30 minutes before sunrise for Chicago, Mercury achieved its highest altitude of 10.0° on JAN 13. Through a telescope that same day Mercury appeared in dichotomy, i.e. 50% illuminated like a Half Moon. Prior to that appeared as a crescent and afterward gibbous. Mercury reached its Greatest Western Elongation of 24.1° on JAN 19. While increasing in brilliance, Mercury will fall to superior conjunction behind the Sun on MAR 07.

   The Moon will appear near Mercury on 2017 JAN 25 & FEB 25. There will be no lunar occultations of Mercury during this apparition.

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

Mercury Angular Diameter - 2016-17

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

Mercury Illumination Phase - 2016-17

Graph of the percentage of Mercury’s apparent disk illuminated

Mercury Stellar Magnitude - 2016-17

Graph of the brightness of Mercury measured in stellar magnitude

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© Curt Renz

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