Observing celestial objects in the night sky, specifically the planets, can be a tremendously rewarding experience. Although you may have seen planetary pictures on the internet, the first time you actually aim your telescope and peer through to another world for the first time is simply unmatched.
Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune raise a plethora of questions about the universe we live in and its origins. That's why viewing them close up through a telescope can be so fascinating.
However, many questions arise. How exactly do you go about observing the planets? When are the best times to view Mercury? What's the ideal magnification for viewing Neptune?
Don't worry, in this guide we will review some key insights to get you started on how to observe the planets in 2023.
First steps to observing the planets with a telescope
Before getting into the actual observation of each planet, there are a few general tips you should know in order to improve your viewing experience. They are as follows:
- Avoid Atmospheric Turbulence - Make sure to set up your viewing equipment in an area away from the bright city lights or other brightly lit areas. Light pollution can drastically impact your observation abilities.
- Reach Thermal Equilibrium - Position your telescope outside at least 30 minutes before use in order to give it a chance to adjust to ambient temperatures. This will help to avoid distortion and condensation buildup on your equipment.
- Collimate - Collimation is the process of aligning all components in a telescope to collect more light and provide optimal image clarity. It often involves the adjustment of the telescope's mirrors to ensure that light reflecting on the main mirror forms an image in the precise center of the eyepiece. If applicable, make sure your telescope is properly collimated.
- Open Both Eyes - When looking through the telescope's eyepiece, keep both eyes open. By relying on one eye only, muscle fatigue can distort your vision.
- Dark Vision - Allow at least 20 minutes for your eyes to properly adjust to the darkness of your environment before attempting to peer through your telescope.
With these general guidelines covered, let's dive further into each of the readily observable planets in our solar system. For easy navigation of this guide, you can click on a specific section below.
- How to view Mercury
- How to view Venus
- How to view Mars
- How to view Jupiter
- How to view Saturn
- How to view Uranus
- How to view Neptune
How to view Mercury
Mercury, named after the Greek god Hermes, is the smallest and closest planet to the Sun in our solar system. Its mean radius is 2,439 km (1,516 miles) which is .3x Earth's radius. Mercury zips around the Sun in just 87.969 days and its apparent magnitude is between -2.48 and +7.25.
The first thing to note about observing Mercury is to be very careful, especially when using a telescope. Since Mercury's orbit is so close in proximity to the Sun, you should never try to view Mercury during broad daylight. By accidentally looking directly at the Sun you could cause permanent damage to your eyes. It is not worth the risk.
Ideally, you should wait for moments of favorable separation between the Sun and Mercury for safe observations. These optimal moments of separation are known as "greatest elongation". Mercury's "greatest eastern elongation" occurs when the planet is farthest east of the Sun and Mercury's "greatest western elongation" occurs when the planet is farthest west of the Sun.
How to locate Mercury
Since Mercury is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Mercury in 2023
- January 30, 2023 - Greatest western elongation (just before sunrise, look low in the eastern sky).
- April 11, 2023 - Greatest eastern elongation (just after sunset, look low in the western sky).
- May 29, 2023 - Greatest western elongation (just before sunrise, look low in the eastern sky).
- August 10, 2023 - Greatest eastern elongation (just after sunset, look low in the western sky).
- September 22, 2023 - Greatest western elongation (just before sunrise, look low in the eastern sky).
- December 4, 2023 - Greatest eastern elongation (just after sunset, look low in the western sky).
Recommended telescope magnification for viewing Mercury: at least 50x.
Mercury features to look for
When observing Mercury, try to identify its phases. They are similar to the Moon's lunar phases. The 116-day synodic cycle of Mercury starts with a new phase (inferior conjunction), then it moves to its 1st quarter phase (greatest eastern elongation), arrives at its full phase (superior conjunct), transitions to its 3rd quarter phase (greatest western elongation), then it repeats that cycle.
How to view Venus
Venus, named after the Roman goddess of love and beauty, is the 2nd planet from the Sun in our solar system. The planet's mean radius is 6,051 km, which is .94x Earth's radius. It takes 224.7 days for Venus to complete its orbit around the Sun. The Venus atmosphere is composed of 96.5% carbon dioxide and 3.5% nitrogen. Surface temperatures reach up to 900° fahrenheit making Venus the hottest planet in our solar system. The planet's apparent magnitude is between -4.92 and -2.98.
How to locate Venus
Since Venus is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Venus in 2023
- June 4, 2023 - Greatest eastern elongation (just after sunset, look low in the western sky).
- October 23, 2023 - Greatest western elongation (just before sunrise, look low in the eastern sky).
Recommended telescope magnification for viewing Venus: at least 50x.
Venus features to look for
When observing Venus, try to identify the phases of Venus. Venus' phases are similar to the Moon's lunar phases. The 584-day synodic cycle of Venus starts with a new phase (inferior conjunction), moves to its 1st quarter phase (greatest eastern elongation), arrives at its full phase (superior conjunct), transitions to its 3rd quarter phase (greatest western elongation), then it repeats that cycle.
How to view Mars
Mars, named after the Roman god of war, is the 4th planet from the Sun in our solar system. Its equatorial radius is 3,396 km, which is .5x Earth's radius. It takes Mars 687 days to orbit the Sun. Mars has 2 moons, Phobos and Deimos. The planet's apparent magnitude is between -2.94 and +1.86.
How to locate Mars
Since Mars is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Mars in 2023
- Mars reached opposition on December 8, 2022. As of that date, Mars has been the brightest it will be in the sky until it fades by September 2023.
Recommended telescope magnification for viewing Mars: about 35x per inch of aperture up to 7 inches and 25x to 30x for larger telescopes.
Mars features to look for
- The 2 moons of Mars:
- Phobos (magnitude +11.8)
- Deimos (magnitude +12.89)
- Polar ice caps.
- Olympus Mons, the largest volcano in the solar system. It is about the size of the state of Arizona.
- Valles Marineris, one of the largest canyons in the solar system.
How to view Jupiter
Jupiter, named after the Greek god Zeus, is the 5th planet from the Sun in our solar system. The planet's equatorial radius is 71,492 km, which is 11.2x that of Earth's radius. As the largest planet in the solar system, Jupiter's mass is 2.5 times all the other planets combined. A full rotation around the Sun takes Jupiter 11.86 years and it has 80 known moons. Jupiter's atmosphere is comprised of 90% hydrogen and 10% helium. The apparent magnitude of Jupiter is between -2.94 and -1.66.
How to locate Jupiter
Since Jupiter is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Jupiter in 2023
- November 3, 2023 - Jupiter reaches opposition.
Recommended telescope magnification for viewing Jupiter: at least 25x to 35x per inch of aperture.
Jupiter features to look for
- Jupiter's 4 brightest Moons:
- Io (magnitude +5.0)
- Europa (magnitude +5.3)
- Ganymede (magnitude +4.6)
- Callisto (magnitude +5.7)
- Great Red Spot. Discovered in 1665 by Italian Astronomer Giovanni Cassini, the Great Red Spot is located in Jupiter's Southern Hemisphere.
- Belts and Zones. Belts refer to the dark colored bands and zones refer to the white colored bands.
How to view Saturn
Saturn, named after the Roman god of wealth and agriculture, is the 6th planet from the Sun in our solar system. Its equatorial radius is 60,268 km, which is 9.4x that of Earth's radius. It takes Saturn 29.5 years to complete a revolution around the Sun and it has 83 known moons. Saturn's atmosphere is made up of predominantly hydrogen and helium. The planet's apparent magnitude is between -0.55 and +1.17.
How to locate Saturn
Since Saturn is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Saturn in 2023
- August 27, 2023 - Saturn reaches opposition.
Recommended telescope magnification for viewing Saturn: at least 25x to view Saturn's Rings.
Saturn features to look for
- Saturn's Rings. The main outer A ring and the middle B ring are separated by a dark gap referred to as the Cassini Division.
- Titan, the brightest of Saturn's 82 moons shining at magnitude +8.4.
How to view Uranus
Uranus, named after the Greek god of the sky, is the 7th planet from the Sun in our solar system. The planet's equatorial radius is 25,559 km, which is just slightly north of 4x Earth's radius. It takes Uranus 84 years to orbit the Sun and it has 27 known moons. The planet's atmosphere is mainly composed of hydrogen and helium.
Uranus is the farthest planet that can be seen with the naked eye (though with various levels of difficulty). Its apparent magnitude is between +5.38 and +6.03. The dimmest magnitude that the human eye can see is around +6.0.
How to locate Uranus
Since Uranus is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Uranus in 2023
- November 13, 2023 - Uranus reaches opposition.
Recommended telescope magnification for viewing Uranus: at least 100x.
Uranus features to look for
- Oberon and Ariel, the brightest of Uranus' 27 moons shining at magnitude +14.1 and +14.4 respectively.
How to view Neptune
Neptune, named after the Roman god of the sea, is the 8th planet from the Sun in our solar system. The planet's equatorial radius is 24,764 km, which is nearly 4x that of Earth's radius. It takes Neptune 164.8 years to complete its orbit around the Sun and it has 14 known moons. Neptune's atmosphere consists of 80% hydrogen, 19% helium, and trace amounts of methane.
Neptune is the only planet that cannot be seen without a telescope. With an apparent magnitude between +7.67 and +8.00, it is extremely dim in the night sky. An apparent magnitude of +6.00 is the dimmest object the human eye can see without assistance.
How to locate Neptune
Since Neptune is in constant motion, it will always appear in a different place in the sky depending on the day, month or season during which you are searching for it. Therefore, the best advice we can provide on how to locate Mercury on your preferred day of viewing is to use free software, such as Stellarium. You may also use other free online star charts as well as a plethora of astronomy apps for use on your mobile device.
Best times to view Neptune in 2023
- September 20, 2023 - Neptune reaches opposition.
Recommended telescope magnification for viewing Neptune: at least 150x to see the planet's disc shape, at least 700x to see the planet's detail.
Note: as a general guideline, your telescopes maximum useful magnification will be roughly 50x its aperture (in inches).
Neptune features to look for
- Great Dark Spot.
- Triton, the largest of Neptune's 14 moons, shining at magnitude +13.47.
What about Pluto?
Some of you may be wondering why Pluto wasn't mentioned in this list of planets. Unfortunately, after being recognized as the ninth planet in our solar system for over 70 years, in 2006 the International Astronomical Union (IAU) updated Pluto's status to a dwarf planet.
Why? Because the IAU members redefined the basic characteristics that should determine what defines a celestial object as a planet.
The new criteria dictated that a planet is a celestial body that (a) is in orbit around the sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium shape and, (c) has cleared the neighborhood around its orbit.
Although Pluto adheres to points (a) and (b), point (c) is not met. As a result, the committee decided that because Pluto does not have gravitational dominance, it is considered a dwarf planet.
Start viewing the planets
You now have a much better understanding of how to start observing the planets in our solar system. However, words on a page can only provide so much insight, the real learning will come from the actual viewing experience.
So why wait? Dust off your telescope or grab a quality pair of astronomy binoculars, and start observing.
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