How to Spot Mercury in the Evening Sky

If you've never seen this fleet-footed planet, now is a great time to look for it in the evening sky after sunset.

Right now Jupiter reigns supreme in the evening sky after sunset. But it's not the only bright planet in view. For the next week you can spot Mercury low in the west about 45 minutes after sunset. If you're never seen the innermost planet before, this is a good month to look for it.

Because it's the innermost planet, Mercury is never far from the Sun in the sky. This proximity makes it tricky to spot  — when Mercury is above the horizon, the Sun usually is too; when the Sun has dropped from sight enough for the sky to be dark, it's usually dragged the planet along as well. Even in the very best of geometric circumstances, Mercury and the Sun can never appear more than 28° apart in the sky.

Mercury on April 15th

If your sky is clear after sunset, Mercury is easy to spot low in the west during mid-April.
Sky & Telescope diagram

Moreover, this fast-moving planet orbits the Sun so quickly, once every 88 days, that it can't stay put for very long. Instead, it jumps between the morning and evening sky multiple times each year.

But some times are better than others for trying to glimpse this celestial speedster — and this is one of those times. Mercury is in the midst of its best evening-sky appearance of the year. And its angular separation from the Sun will reach 20°, what astronomers call greatest elongation, on April 18th.

So if you've got an unobstructed view toward west and it's clear at sunset, step outside for a few minutes to track down this elusive planet. Bring along binoculars if you have them, so you can take in one last view of the Pleiades, somewhat higher up in the western sky, before they sink out of view in the coming weeks.

But don't wait too long! Mercury is getting a little dimmer with each passing day, and by early May it will be too low and faint to spot.

If you to see how this planet looks up close, check out Sky & Telescope's exclusive Mercury globe, prepared in collaboration with NASA's Messenger spacecraft team.

5 thoughts on “How to Spot Mercury in the Evening Sky

  1. Joe StieberJoe Stieber

    I’ve already spotted Mercury on five evenings this month, April 3, 5, 8, 12 and 14, 2016. In each case, I initially spotted it with binoculars (16×70 or 10×50), then was able to pick it up with unaided eyes. The two dates this week, April 12 & 14, Mercury was still up in relatively dark twilight and was quite prominent with unaided eyes. Last night, April 14, I had my 80 mm apo refractor out for a look. After getting Mercury in the scope field at low power, I put in a 4.7 mm eyepiece (102x) and immediately noticed that it appeared half illuminated with a nominally straight terminator, like a first-quarter moon. I probably follow Mercury more than the average observer, but I’m paying special attention to this final elongation leading up to the transit on May 9th.

    1. AlphaCentauri

      I’ve also seen it several times this month.I find it with binoculars as well.I have a 70mm refractor at the present time, but a 130 mm reflector is in the mail. It should be here Monday, and I’ll point it at Mercury.

  2. Pleiades Co.Pleiades Co.

    I have spotted mercury 3 times in a row and a fourth today. The third i used a 76mm flector and noticed a terminator that looked like a wanning gibbous

  3. Jakob

    Mercury still easy with the unaided eye in the cold spring evening from my residence in Helsingborg, Sweden. If it stays this cold and clear, Mercury will be visible for another 3 days ! J

    1. Joe StieberJoe Stieber

      My last view was on the evening of April 20, 2016, since the past two evenings have been cloudy. It’s supposed to clear this evening (April 23), and if so, I’ll be out again with my 80 mm refractor. On April 19 & 20, besides being a relatively easy object with unaided eyes, I could discern the crescent shape in the scope, but it was more like a fat banana because of degraded seeing at its low altitude. If seeing permits, the crescent should be more prominent this evening as it will be down to 22% illuminated. On the downside, Mercury’s magnitude will have dropped to +1.1, so yes indeed, it’s getting dimmer as the extent of illumination shrinks. So far, I’ve seen Mercury on ten different days this month (April 2016). If seen tonight, it will be the eleventh. And goodness, it’s just 16 days until the transit!

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