Mercury at Inferior Conjunction

orbital-positions   Monday September 12th the innermost planet Mercury reaches inferior conjunction. At inferior conjunction Mercury will move between the Earth and the Sun – much like the position of the Moon at new phase. The graphic to the right shows the planet positions relative to the Earth and Sun for both inner planets and outer planets.

mercury at inferior conjunction   While at this inferior conjunction Mercury will not be directly in line with the Earth and the Sun – on the ecliptic. Mercury has an orbital inclination of 7o with respect to the ecliptic. So like our Moon, Mercury during each complete orbit, will cross the plane of the ecliptic moving north (ascending node) and also moving south (descending node). In this situation Mercury is still south of the ecliptic but heading toward its ascending node on September 23rd.


Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

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