by If there is one thing that has baffled me most in over 50 years of being involved in astronomy outreach, it is the way most astronomy books make it seem like a very challenging object, if not nearly so. it is impossible to see the planet Mercury. In fact, he earned the nickname of this planet as the “unfortunate planet.”
Here, for example, is a quote taken from the book “The ABC’s of Astronomy” by Roy A. Gallant (Doubleday & Company, Inc. 1962): “Mercury is the hardest planet to look at, it has little to offer, and difficult to see because it is so small and so close to the sun.”
This is certainly not inviting to someone who would want to see Mercury for themselves. And yet, viewing prospects are not as bleak as this quote suggests. In fact, on certain occasions, Mercury is not so elusive at all. You just need to know when and where to look, and find a clear horizon. It is important, for example, that Mercury be placed as directly above the sun as possible, a condition best met just after sunset in late winter or early spring and before sunrise in autumn or early in the winter.
Related: The night sky, March 2024: What you see tonight
Mercury is called an “inferior planet” because its orbit is closer to the sun than Earth’s. Therefore, it always appears from our point of view to be in the same general direction as the sun. Therefore, few people laid eyes on him; there is even a rumor that Copernicus, who lives in northern Poland, did not see it. But it’s not hard to see. You need to know when and where to look, and find a clear western horizon.
A three week window
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Need a telescope to get out there and see Mercury? We recommend the Celestron Astro Fi 102 as the top choice in our best beginners telescope guide.
And for those living in the Northern Hemisphere, now we are in the middle of a perfect “window of opportunity” to see Mercury in the evening sky. That window, which will close after March 31, will continue to give you a good chance to see this so-called “unforgettable planet” with your own eyes.
Currently, Mercury is visible about 45 minutes after sunset, very close to the western horizon. However, if your sky is clear and there are no high obstructions to your view (such as trees or buildings) you should have no trouble seeing it as a very bright “star” shining with just a trace of your fingernail yellow-orange. Currently, Mercury is shining at a very bright magnitude –1.3. In fact, among the stars and planets, Mercury is now a very respectable fourth, behind Venus, Jupiter, and Sirius (the brightest star).
In the following evenings, Mercury will decrease – slowly at first – in brightness, but it will also reach its greatest elongation, 19 degrees east of the sun, on March 24. a similar star Arcturus in Boötes), Mercury will appear 22 degrees below and to the right of Jupiter. Your fists are clenched at arm’s length about ten degrees wide. Therefore, Mercury will be located directly above “two fists” to the lower right of Jupiter. Mercury will also be setting more than 90 minutes after the sun. In fact, from 20 to 28 March, it will be setting after the end of the afternoon evening in the dark sky.
As a result, this will be the best evening apparition of 2024 Mercury.
Mercury, like Venus, appears to go through phases like the moon. During early March, just when Mercury began to appear very low in the bright western sky, it was an almost complete disk, which is why it now appears almost as bright as Sirius . By the time it reaches maximum elongation, it will appear 43 percent illuminated, and the amount of its surface illuminated by the sun will continue to decrease over the coming days. Therefore, when it begins to turn back into the vicinity of the sun after March 24, it will disappear at a relatively fast pace.
Indeed, on the evening of March 31, the brightness of Mercury will have fallen to magnitude +1.4; a trifle dimmer than the star Regulus in Leo and only 1/12 as bright as it is now. In a telescope it will appear as a narrowing crescent phase. This will probably be your last view of it, as Mercury will be invisible by early April due to its rapid swing and descent into the brighter sunset glow.
More than a thousand degrees difference!
In ancient Roman mythology, Mercury was the swift messenger of the gods. The planet is well named because it is the closest planet to the sun and the fastest planet of the solar family, averaging about 30 miles per second; making his annual trip in 88 days around the world.
Interestingly, the time it takes for Mercury to rotate once on its axis is 59 days, so that all parts of its surface experience periods of intense heat and extreme cold. Although its average distance from the sun is only 36 million miles (58 million km), Mercury has by far the greatest temperature range: 790° F (420° C) on the dayside; -270° F. (-170° C) on its night side.
Dual Identity
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In the pre-Christian era, this planet actually had two names, because it was not noticed that it could appear on one side of the sun and then on the other. Mercury was called Mercury when he was in the evening sky, but when he appeared in the morning he was called Apollo. It is said that Pythagoras, around the fifth century BC, pointed out that they were really one and the same.
If you’re hoping to look at Mercury, our guides to the best telescopes and best binoculars are a great place to start. If you’re looking to photograph the night sky in general, check out our guide to photographing the planets, as well as our best cameras for astrophotography and the best lenses for astrophotography.
Note to the Editor: If you draw an image of Mercury and want to share it with Space.com readers, send your photo(s), your comments, and your name and location to spacephotos@space.com.
Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Free natural history magazine,the The Farmers’ Almanac and other publications.
