Mercury approaching inferior conjunction

Event Date: March 2nd

Time: 6:00 PM

Brief

   Mercury's retrograde over the last eight days has meant a "plunging" towards the Sun.  After all, at this time of year when it is north of the Sun-- with our star moving in that direction.  Mercury's retrograde means that the declination gap shrinks dramatically between the two.  Coupled with Mercury rapid waning in phase and hardly a change in distance from us in comparison, the planet's magnitude has dropped quickly during the retrograde and it hasn't been visible the last few days.

   What I will show below, following Mercury's position to the Sun with the celestial guidelines, is a magnified showing of Mercury as a thin waning crescent.  Although it is buried in the Sun's glare and too dim, this is simply to show how most of Mercury's illuminated side is facing away from us, while still a tiny disc a little less than 60 million miles from us.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   

   As shown in image two, I magnified Mercury at only about 500x, despite this making it hard to see the 1% illumination.  The reason for this is simple: even when at a better elongation from the Sun, Mercury is often too deep in atmospheric pollution to magnify; too much refraction of the Sunlight reflected off of it leads to lots of "ripple" making the phase shape less definite.

   One thing to realize is that Mercury is still only a couple of weeks from perihelion and therefore, not as close to us as it would be for near-inferior conjunctions in during December and January; these are the months when we are closer to the Sun for our perihelion and days sandwiching it.  When Mercury is at aphelion and we are at perihelion, that is when it closest to us and therefore, its disc size is a little bigger.  Its magnitude is not different as a result of the small percent of illumination, yet I thought to mention this.  For upcoming inferior conjunctions, coming up in the middle and late this year, I will compare Mercury's distance from Earth.  Once again, even if not visible to us because of the Sun and its phase, it is still fun to notice this, considering the shapes of our orbit and Mercury's.  That, along with remembering that the Sun is not in the center of either, or any planets' orbit.