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You get an automated phone solicitation. What are they peddling? It’s a glimpse of the planet Mercury. Not a chance, right? But give me a couple minutes and I’ll wager you’ll be “sold” and desperately want to see the fast-moving “winged” Mercury.
Mercury’s Best Appearance of 2023
The facts: April 1 to 15, 2023 is the best opportunity to spot the elusive planet Mercury—usually too close to the Sun to be visible. On April 11, 2023, Mercury reaches its “greatest elongation” or greatest distance from the Sun. This means it’s far enough away from the Sun to be seen. It’ll be the best Mercury elongation of the year. Additionally, Mercury is near zero-magnitude at this time, making it brighter than the stars currently near it.
Still not convinced it’s worth your time? Here’s why you’ll want to seek the innermost planet to the Sun:
First, because absolutely everyone has seen Venus, since it’s so dazzling after sunset. You get no bragging rights for noticing Venus.
Second, only two planets lie closer to the Sun than Earth, and both have the hottest surfaces in the known universe, so it’s a chance to hook up with weirdness.
Third, they’re the only planets with no moons, making them unique loners.
Fourth, many notable astronomers confess they’ve never seen the innermost, fastest moving world, with the greatest temperature extremes science has yet discovered. A place with ice just a few yards from heat that would melt lead.
Finally, there’s all the mythology. This is Usain Bolt with wings on his feet.
Mercury’s usually a challenge, but not now. We’ve got a “special offer” valid only for the first half of April. Start by imagining a moth frantically circling a flame. To see the moth you naturally have to face the fire. Similarly, Mercury whizzes closely around the sun every 88 days. But facing the Sun in order to see Mercury would logically mean staring into the blue daytime sky, and there’s no upside in doing that! So smart people like you and me wait until the Sun has set, after picking a date when Mercury’s orbital position places it above the Sun so that it’s visible just above the horizon after the Sun has dipped below the skyline.
In other words, the horizon blocks the blinding solar brilliance. But that still leaves us with a balancing act. We want to observe when Mercury is near the upper edge of its orbit but also is very nearly at its greatest brightness, since its brilliance varies more than any other planet. Also, since it’s never far from the Sun, we can count on it being low soon after sunset. But if we wait until full darkness has fallen then the Sun has sunk too far down and Mercury will have set.
We’ve figured it all out for you. The result will be a strange satisfaction, an ineffable feeling of accomplishment that only Mercury observers can understand. And you are about to be one of them.
Best Date and Time to See Planet Mercury
Mark your calendars. We know Mercury is at its brightest at the start of April (near zero-magnitude) but also we’re aiming for a date and time when Mercury is 10 degrees above the horizon a half hour after sunset.
How do you know what 10 degrees above the horizon is? Hold out a vertical clenched fist at arms’ length. Vertical means the fist is clenched as if you’re grasping a flag staff. Close one eye and place the bottom of that fist straight out horizontally at eye level. The top of that fist will mark off 10 degrees.
Here’s why this is so cool: even if you’re looking toward hills or other obstructions, the top of that fist will instantly show you whether Mercury will be “in the clear” at that location. Obviously if you’re overlooking an unobstructed western-facing expanse like being in Buffalo and facing Lake Erie, or looking past an Indiana wheatfield, the top of the fist will be in the sky. If it’s not, go somewhere that’s in the clear for that fist-top. Now you’ve got your location, the place you want to be the next clear night.
The next issue is what time to look. It’s going to be something between 7:00 and 8:00 PM but the exact time will vary depending on your location’s distance from your time zone boundary. But don’t give that another thought. Forget about clocks and simply go out when evening twilight is deepening (about 45 minutes after sunset). You want it to be just dark enough for the first stars to be appearing. Or, for more specific guidance, if you can see the stars of Orion’s belt you’ll easily see Mercury. But don’t wait until it’s too dark, when lots of stars will be out but Mercury will have sunk too low. A balancing act, remember?
Bottom-line: As April starts out, Mercury is at its brightest. But starting around Easter Sunday, although Mercury is less bright, it’s a bit higher up and therefore remains visible while twilight deepens and more stars come out, making the innermost planet more prominent. From Easter Sunday through (April 9) through Mercury’s greatest elongation (April 11), the brightness and height of Mercury should be at its very best.
How to See Mercury
As the sky is darkening, look west. Dazzling Venus will grab your attention first. She’s the brightest object in the night sky other than our Moon. Then look downward for Mercury which will be halfway between Venus and the horizon below Venus, although a bit to the right of that line. If you see any star in that location you’ve found Mercury, simple as that. Don’t expect anything brilliant. Mercury is 600 times less bright than Venus. But it’s there and no other planet or star is anywhere near that spot. Additionally, it’s near zero-magnitude at this time, making it brighter than the stars currently near it. Just look intently for that glowing “star” before it drops below the horizon, chasing the setting Sun.
By April 15, Mercury fades from view. The tiny planet gets dimmer and lower in the sky, soon to be chasing too close to the Sun again.
If you look on the days at the times I shared with you, everything should work out, given clear skies. And you will have joined an exclusive club, and probably be the only one of your friends, to have laid eyes on the smallest, fastest, hottest planet of them all. And as your salesmammal, let me finish by letting you know that as an introductory rate, the price for seeing Mercury is free!