How to observe mercury through telescope

Mercury is the innermost and the smallest planet in our solar system. Mercury’s approximate diameter, which depends on its distance from Earth, can vary from 4.5 arcseconds at apogee to 12.9 arcseconds at perigee. It is less in size than Ganymede, Callisto, and Titan and noticeably smaller than Mars.

Nonetheless, Mercury is significantly denser than the Moon or Mars because it has an unusually large metal core.

Also, it can be quite difficult to locate it through a telescope. The fact that it is positioned quite near to the Sun restricts the times of the year when it may be spotted, and its fairly small size may make it hard to notice even in this situation.

The downside of being so near to the sun is that Mercury is never visible in a really dark night sky – only dawn and dusk – and then only for a few days at a time.

Nevertheless, with some preparation and knowledge, it is attainable to see Mercury through a telescope. With the proper gear and suitable seeing conditions, you can spot this elusive planet.

In this article, you will find little tips for observing Mercury through a telescope and will learn the various ways to detect this elusive planet.

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Proper gear and accessories

The suitable enough telescope for observing Mercury depends on several factors. The aperture size, the quality of its optics, and the mount are on the list of important aspects.

If a telescope has a larger aperture, it will usually help you to receive a more qualified picture.

This is because more light will be gathered and the resolution of the provided image will be higher. A telescope with an optical system of a better level of quality will also be a quite suitable choice for observing Mercury, as it will provide a more sharp, clear picture of Mercury’s surface.

A telescope with an aperture size of no less than 60 mm and a long focal length would be an excellent choice for examining Mercury. In case you will mount a telescope on an equatorial mount, it would also be quite useful, making it more effortless to find the planet while it is moving across the sky.

But it’s better to consider that the most significant aspects are your skills, experience, and seeing conditions. Even not such a big telescope with an experienced viewer can produce a wonderful view of the planet in suitable observing conditions.

So, you don’t need a very big telescope to be capable to spot Mercury.

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Suitable times to observe Mercury

It is fairly frequently said to be elusive, but not because it is dim. In fact, at its most radiant, Mercury shines at a magnitude of -1.9, which is more shining than Sirius, the brightest star in our night sky.

Planet Mercury is elusive because it is observable only close to the western horizon at dusk or the eastern horizon at dawn for two-week intervals a few times during the year. It is better to try to detect Mercury through a telescope at “greatest eastern elongation” or “greatest western elongation” from the Sun.

These are the periods when Mercury is at its most far point from the Sun as glimpsed from Earth, becoming noticeable in the evening or morning sky, respectively.

The greatest eastern elongation happens when Mercury is on the other side of the Sun as noticed from Earth and starting to rise just before sunset. It is probably the most ideal time to locate the planet in the evening sky.

When Mercury is on the exact side of the Sun as noticed from Earth, the ideal time to glimpse the planet is in the morning sky, just after sunrise, when it has achieved its greatest western elongation.

During the greatest eastern and greatest western elongation, a planet becomes especially well-suited for checking out.

Mercury is also seeable for a brief time around inferior conjunction when it passes between the Earth and the Sun.

The fact that it is the closest planet to the Sun makes it challenging to detect, even when it is the most appropriate time to examine it. But if you select the proper time, and will use the help of a telescope, you can most likely successfully spot it.

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Bits of advice to get a great view of Mercury

Viewing Mercury can be a quite hard job for you, especially in case you are a beginner. These particular tips will help to improve your experience:

  • The great time to find Mercury is when it is at “greatest eastern elongation” or “greatest western elongation” from the Sun, so you need to arrange your observation consequently.
  • If you wish your quest to spot Mercury to be successful, you can use the help of the Planetarium app.It can be easily downloaded from the Apple App Store or Google Play, and you’ll immediately have a lot of knowledge at your disposal.
  • It is quite useful to be aware that you’re glancing at Mercury through the very thick layer of Earth’s atmosphere. Due to that, Mercury will twinkle in the sky fairly brightly.
  • It would be good if you use color filters with Wratten Numbers like #21 Orange. With their help, the sky’s brightness will be reduced. It will significantly enhance your experience.
  • If you wish to detect Mercury in the early morning, you should get up quite early, before the sun rises. The Sun’s light can fairly swiftly make it unattainable to notice the planet. If you begin to watch toward the east no less than an hour before sunrise, it almost certainly will be attainable to see Mercury.
  • If you want to examine Mercury during the evening when it is close to the western horizon, it is advisable to begin preparations before sunset. It would be the perfect option if you begin to look just right after the Sun goes below the horizon. You must have about an hour to examine the planet properly.
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What to see when you examine Mercury

So, what can notice when the time is suitable for finding Mercury? Despite some possible difficulties, you will be able to find the planet Mercury with using of a telescope and without it.

Naked eye

So, is Mercury visible to the naked eye?

If you look at it with the naked eye, it seems like a shining point object, resembling a star, with its magnitude ranging from as bright as mag. –2.8 to a dim mag. +7, when you can only spot it through binoculars or a telescope.

Nevertheless, if you take some time to glimpse it without any equipment, you will notice a slight, rosy, golden tinge that differentiates it from the starry background.

Also, if near the horizon, it can ‘twinkle’ like a star, because of atmospheric turbulence.


A pair of low-powered binoculars will help you discover the planet, especially at times when it is quite dim.

Nevertheless, since Mercury is frequently observed against more bright skies, a telescope will be the most suitable choice and quite easily help you find it.

For the best experience, you’ll wish Western or Eastern horizons to be clear (depending on when you’re doing your observation).

With all planetary astronomy, observing conditions will significantly impact examinations. Because of that, try to catch Mercury at its highest probable altitude, no less than one hour outside of sunrise or sunset times.

Because of Mercury’s nearness to the sun, it will never be entirely observable through your telescope. Although the planet is not visible at its full phase during superior conjunction and at its new phase at inferior conjunction, even in the brief windows of opportunity in between the changes in its phases are noticeable.

If you use a 3-inch scope, you will glimpse Mercury’s phases fairly easily.

You will probably be able to see rather distinct shapes and surface features on the planet. However, Mercury is too distant for you to see craters with a usual telescope.

You will, nevertheless, be able to track Mercury during its first and last quarters. Mercury appears quite comparable to our moon during those phases.

Also, the Mercury presents itself slightly pink unless you’re examining it through a special color filter.

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Frequently asked questions

Can you see Mercury through a telescope?

Yes, this is achievable. It can be fairly problematic to notice Mercury with the naked eye but you can detect it even in the daytime with a telescope if you know where you need to begin to seek. You can see a small disk when Mercury is close to the Earth, also you can notice phases that resemble the Moon’s.

What color is Mercury in a telescope?

Even though Mercury is generally white, its proximity to the horizon gives off a pinkish hue. This follows the exact same logic as to why our Sun appears reddish during sunrise and sunset.

Why is it hard to observe Mercury with a telescope?

It can be quite difficult to notice because it is never far enough away from the Sun to be noticed in a dark sky, i.e., it is only ever seeable in the brighter skies of dawn and dusk.

While you can detect Mercury with the naked eye, it won’t be attainable to detect any details.

Anyway, while you won’t notice craters, on nights of fairly satisfactory seeing and minimal level of turbulence, some surface details can be examined with larger-aperture telescopes.

What is the best way to view Mercury?

It is attainable to observe Mercury with the naked eye during times right before and after the sun has set, which provides enough light pollution to contrast the shadow of Mercury. An ideal time to try and catch Mercury with your naked eye is 90 minutes before sunrise or after sunset.

But the best option is the use of the telescope. You will receive a more clear image, also it will allow you to see some details of the surface of the planet.
If you wish to receive the image of Mercury that will be satisfactory, examine it while its elongation from the Sun is happening. Try to use at least a 60-mm aperture telescope for a better experience.

Also, it would be great if you will be able to look at the planet while it transits. When Mercury transits in front of the Sun, it goes right between the Sun and the Earth every so often.

When it is happening, you can notice it as a tiny black dot quickly crossing the solar disk.


Mercury is the smallest planet in our solar system. Also, it is an innermost planet, but it is one of a kind.

Mercury is far more challenging to locate than other bright planets because it’s the planet closest to the Sun. Nevertheless, Mercury’s phases are worth checking out, not to mention the prestige and sense of accomplishment that comes from seeing a rarely glimpsed planet in our solar system.

Observing Mercury through a telescope can be a fairly difficult job, but thanks to this article, you can manage quite effortlessly.

Firstly, you have to choose the fitting gear and accessories that you will be using for observing Mercury. Secondly, it is better to select a suitable time to find Mercury through a telescope. Your skills are quite important regarding the practical observation of the Mercury planet.

You can also locate Mercury without a telescope, but in this case, it won’t be doable to notice any details.

If you need to read about how to observe mercury with telescope, please read our article.

Ida Stewart

I have had the incredible opportunity to work as a tour guide at the planetarium for over 5 years. Ever since I was a child, astronomy has held a special place in my heart, and I have nurtured a deep passion for exploring the wonders of the universe. Among all the celestial bodies, Mars has always fascinated me the most, captivating my imagination with its mysterious allure.

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