May 30, 2020

Astro-Event of the Week, September 9th-15th, 2008: Mercury Reaches Greatest Elongation.

Mercury is an elusive world.

Legend has it that Nicholas Copernicus himself never spotted the fleeting world. This week, Mercury reaches greatest elongation, and provides us with a chance to top one of the greats. A good pair of 7×50 binocs will help in the feat; start sweeping low to the west immediately after sunset. Bright Venus will be the first to pop into view; keep an eye out for faint Mars in the same field. Mercury, at magnitude -0.5, will be off to the lower left. See another point of light off to the left? You’ve found the star Spica, the brightest in the constellation Virgo.

The Astro-word of the week is Elongation. This simply refers to an inferior planet’s (i.e. Mercury or Venus) observed angular separation from the sun. This month’s elongation of Mercury is a poor one from the Northern Hemisphere, as it places Mercury in the weeds. Folks down under will have better luck!

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