Mercury is sometimes referred to as the “elusive planet” because it’s usually hidden in the glare of the Sun. However, during March, skywatchers are in for a treat as it will be quite easy to see, especially during the second half of the month.
On March 6th, Mercury passes superior conjunction (on the far side of the Sun) and by the 15th it is 9 degrees to the east of the setting Sun. Around that time it can be spotted with binoculars very low due west about a half hour after sunset. It becomes an easy naked-eye target in mid-twilight a few days later.
On April 1st, Mercury will reach greatest elongation (19°) from the Sun. This marks its best evening apparition of 2017 for mid-northern skywatchers, with the planet setting after evening twilight ends – about 90 minutes after sundown – for more than a week. Mercury is almost directly above the setting Sun throughout this apparition, since at this time of year the ecliptic makes its steepest angle with the western evening horizon.
Use the Moon To Locate Mercury
On March 29th, just a couple of days past new phase, and only 5 percent illuminated, a lovely sliver of a crescent Moon can be found due west and standing 12 degrees above the horizon 45 minutes after sundown. And situated 10 degrees to the lower right of it will be Mercury, shining at a very bright -0.4 magnitude. What could be easier? Use the Moon as a benchmark on this evening to positively identify Mercury.