Where is Mercury tonight?

How to recognize Mercury with the naked eye

Mercury looks like a bright, steady star sitting low in twilight. In the evening it appears above the western horizon not long after sunset; in the morning it shows above the eastern horizon shortly before sunrise. NASA notes that it is only ever seen near sunrise or sunset. At its best it can rival the brightest stars, and JPL Horizons data show it typically near magnitude 0 around its greatest elongations, the moments when it is farthest from the Sun in our sky. (On the magnitude scale, lower numbers mean brighter.)

Because it is low, Mercury may twinkle, and seen through thick air near the horizon it is easy to mistake for a star. The giveaway is position: a bright point in a still-glowing sky, close to the horizon, in the same direction the Sun just set or is about to rise. A thin crescent Moon or brighter Venus nearby can help you find it.

What binoculars and a small telescope show

Binoculars are the best tool for Mercury. Sweep along the horizon in bright twilight, before the planet is visible to the eye, and it will usually pop out as a tiny star. Once you know where it is, look again without them. Always wait until the Sun has completely set before scanning, and stop in the morning well before sunrise, so there is no chance of catching the Sun in your view.

A small telescope shows a tiny disk, between 4.5 and 13 arcseconds across according to NASA’s fact sheet, which is far smaller than Jupiter. Because Mercury is so low, the air near the horizon blurs and colors the image, and surface detail is out of reach for a backyard telescope. Seeing the planet at all is the achievement.

Why its visibility comes and goes

Mercury orbits closer to the Sun than any other planet. From Earth we see it swing from one side of the Sun to the other and back. When it is east of the Sun, it sets after the Sun and is an evening object. When it is west of the Sun, it rises before it and is a morning object. In between, it passes in front of or behind the Sun and disappears in the glare for a few weeks.

The full cycle, its synodic period, lasts about 116 days, according to NASA. That gives Mercury about three evening and three morning appearances each year, each lasting only a few weeks. Even at greatest elongation, Mercury is never more than about 18 to 28 degrees from the Sun. EarthSky gives this range; it is wide because Mercury’s orbit is markedly elongated, with an eccentricity of 0.2056 in NASA’s fact sheet.

Tips for seeing Mercury

• Pick the right season. EarthSky explains that the evening ecliptic, the Sun’s path, meets the horizon at a steep angle around spring, and the morning ecliptic does so around autumn. That lifts Mercury higher into a darker sky. For the US, the best evening appearances come in late winter and spring, and the best morning ones in late summer and autumn. Other appearances can stay low in bright twilight even at large elongations.
• Find a flat horizon. A beach, a lake shore, open farmland or a high viewpoint works far better than a backyard surrounded by houses and trees.
• Time it right. Start looking as the sky begins to darken after sunset, or in the morning as soon as dawn starts to brighten the east. Too early, and the sky is too bright; too late, and Mercury has set or the sky is washed out.
• Measure the sky with your hand. NASA notes that a fist held at arm’s length covers about 10 degrees, which helps you judge how far above the horizon to search.

For general advice on telling planets from stars, see our guide to finding planets, and for the other planets visible now, the planets page.