The Ultimate Guide to Observing Mars

Beyond Earth's orbit lies the fourth planet from the Sun, Mars—a small, mysterious world that has intrigued humanity for generations. With its fiery, reddish appearance in the night sky, Mars often looks like it is preparing for battle, so it was fittingly named for the Roman god of war.


This guide will help you understand Mars and why it is such a favorable target for amateur astronomers and astroimagers of all skill levels. You’ll find below the key dates for 2025 (oppositions, occultations, and conjunctions), followed by observing techniques, gear recommendations, and Mars facts.

 

Important 2025 Dates and Sky Events

Mars Opposition

  • Date: January 16, 2025
  • Constellation: Gemini
  • Apparent Diameter & Brightness: ~14.5 arcseconds in diameter, shining at magnitude -1.4
  • Significance: Opposition occurs about every 26 months when Earth catches up to Mars in their respective orbits, placing Earth between the Sun and Mars. From our perspective, Mars rises as the Sun sets and remains visible all night.

Lunar Occultation of Mars

lunar occultation of mars

  • January 13, 2025 (Full Moon): The Moon will pass in front of Mars. This occultation is visible from parts of the Americas and Africa. Outside the occultation boundary, observers can still enjoy a close conjunction.
    Mars Opposition Map
  • February 9, 2025: Another lunar occultation of Mars will occur over high latitudes (portions of Russia, China, Canada, and Greenland), though it will not be seen from the United States.

Notable Mars Conjunctions

Mars Conjunction

  • October 21, 2025: Mars and Mercury: The two planets will be separated by about 2 degrees, low in the southwest after dusk.
  • November 12, 2025: Mars and Mercury again: An even closer conjunction—about 1.18 degrees apart—also low in the southwest after dusk.


Why Observe Mars?

Unlike Venus and the outer planets covered in clouds, Mars shows surface detail when viewed through a telescope. Nineteenth-century astronomers noticed lines resembling irrigation "canals" and ever-changing seasonal polar ice caps. These markings caused some to speculate that there could be intelligent life on the planet. Although today we know there are no “little green men” on Mars, it remains a fascinating world to explore with your telescope. Best of all, you can do it right from your backyard—even under light-polluted skies!

 

What is Mars Opposition, Anyway?

Mars opposition happens when Earth lines up directly between the Sun and Mars. During opposition, which only occurs about once every 26 months, Mars rises in the east at sunset and is visible all night.

Close oppositions happen every 15-17 years, when Mars is near perihelion (its closest point to the Sun in its orbit).

  • In 2003, Earth and Mars were just under 35 million miles apart—the closest in ~60,000 years, with Mars appearing 25 arcseconds wide at magnitude -2.8.
  • Less favorable oppositions can be ~62 million miles away, resulting in smaller apparent size.
Mars Diagram


How to Find Mars in the Night Sky

If you’ve been following Mars since a previous opposition, you’ll have tracked it through different constellations. For everyone else, star charts in astronomy magazines or websites are helpful. Astronomy apps like Celestron’s SkyPortal Powered by SkySafari™ (included with every Celestron telescope purchase!) are the most comprehensive and informative tools for real-time updates on Mars’ position, 24/7. SkyPortal offers written and audio descriptions of Mars, a responsive planetarium interface that you can hold up to the sky for instant identification, rise/set times, coordinates, and physical/orbital parameters for Mars.

SkyPortal

The Best Equipment for Viewing Mars

Because Mars is a bright planet, you don’t need to travel to a remote dark-sky site or purchase a lot of specialized gear for thrilling views. When Mars is visible, simply head outside with any optical aid and gaze at our neighboring world. Of course, a bigger budget will get you a larger image scale and enhance the appearance of surface detail, but don’t wait to start observing until you have the “perfect” piece of equipment. Mars is there for all of us to enjoy!

 

Telescopes

You may be surprised to learn that even a small entry-level or travel telescope (60-90mm in aperture) has enough light-gathering ability to reveal some surface markings on the Red Planet. Remember, though, that image scale will be small.

Stepping up to a Schmidt-Cassegrain or Maksutov-Cassegrain with 7” or more in aperture will deliver noticeably better views thanks to its increased light-gathering ability and longer focal length, which boosts image scale and resolution. When purchasing a larger telescope, consider how much weight you want to carry. For a backyard target like Mars, choose something you can set up quickly when conditions are good. 

 

Filters

Added to any telescope, filters enhance subtle features on the Martian surface and in its atmosphere:

  • #80A Blue Filter: Highlights atmospheric clouds.
  • #58 Green Filter or#56 Light Green Filter: Boosts contrast of polar caps, low clouds, and dust storms.
  • #25 Red Filter: Sharpens polar caps and surface features, outlines dust clouds.
  • #21 Orange Filter or#12 Yellow Filter: Increases contrast between light/dark surface features, sharpens dust cloud boundaries.
  • Variable Polarizing Filter: Adjusts light transmission to reduce glare.

You can purchase a variety of filters at once with a Celestron accessory kit (#94306, #94307, #94308, #94119-10, #94303, #94305):

 

What are the different types of eyepiece filters: Colored, Neutral Density and Polarizing? Read More

 

Cameras and Phone Adapters

Capturing Mars on camera has never been more accessible. Whether you want a quick snapshot with your smartphone or a detailed image or time-lapse video, there’s a camera setup for every skill level and budget. Below are the three most popular options—smartphones, DSLRs, and dedicated planetary cameras—along with basic steps and recommended accessories for each:

 

To browse a full assortment of Celestron telescopes and accessories that will make your Mars viewing and imaging experience more enjoyable, click here.

 

What to Look for While Observing Mars

 

Mars Phases

Phases

Mars appears mostly in a gibbous phase, reaching “full” at opposition (unlike Venus’ full range of phases).

 

 

Polar Ice Caps

Polar Ice Caps

Composed of CO₂ (dry ice) over water ice; vary with the seasons.

Land Formations

 

Land Formations

  • Olympus Mons, the largest volcano in the Solar System, and its associated high-altitude clouds (Nix Olympica).
  • Valles Marineris, one of the largest canyons in the Solar System.
  • Dark “maria” like Syrtis Major, Mare Tyrrhenum, and Mare Cimmerium.
  • Dust-covered areas like Hellas Planitia and Arabia Terra.
Dust Storms

Dust Storms

May obscure many surface features. Major storms can become global and last weeks.

Moons (Phobos & Deimos)

Observing Challenge:

Very tiny and close to bright Mars; you’ll need an 11" or larger telescope, excellent conditions, and patience.

 

Helpful Observing Hints

Tip #1:
Choose Nights with Steady Seeing Conditions

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  • Avoid nights with excessively turbulent atmosphere and twinkling stars.
  • Start with low magnification and go higher if views remain clear.
  • Early morning before dawn often offers the most stable air.

Tip #2:
Cool your telescope down

  • Let it sit outside for ~1 hour (or longer for larger mirrors) so it reaches ambient temperature.

Tip #3:
Collimate Your Telescope

  • Newtonian and Schmidt-Cassegrain designs need occasional collimation to achieve their best resolution.
  • Slight misalignment can blur fine planetary details.
Tip #4:
Observe Often
  • Mars rotates once every 24h 37m. Try observing the planet at different times to see new surface areas.
  • Observe regularly for weeks around opposition to see the planet’s changing features.

 

Interesting Facts About Mars

 

Mars

The Red Planet

Mars is often called the "Red Planet" because of its reddish appearance, caused by iron oxide (rust) on its surface.

Aries the Roman God

Roman Mythology

Mars was the god of war and agriculture and the protector of Rome.

Mars size and distance comparable to Earth

Size and Distance

  • Only about half the size of Earth, Mars has a radius of 2,106 miles (3,390 km).
  • Because of its elliptical orbit, Mars ranges from about 128 million miles (206 million km) from the Sun at perihelion to ~154 million miles (249 million km) from the Sun at aphelion.

Martian Days

Martian Days and Years

  • A Martian day (“sol”) is 40 minutes longer than an Earth day.
  • A Martian year lasts 687 Earth days—nearly twice as long as an Earth year.
Mars Season

Seasons

  • Mars has a 25-degree axial tilt, similar to Earth’s, resulting in changing seasons.
  • Each Martian season lasts longer due to the planet’s longer orbit.
Mars Surface Features

Surface Features

  • Olympus Mons: The largest shield volcano in the Solar System, over 21.9 km (13.6 mi) high.
  • Valles Marineris: A massive canyon system stretching ~4,800 km (3,000 mi).
  • Ancient river valleys and lake beds that suggest liquid water once flowed on Mars.
Mars Moons

Moons

  • Phobos (17 miles across) orbits Mars three times a day at ~3,700 miles from the surface and is slowly spiraling inward (~6 feet closer every century).
  • Deimos (9 miles long) orbits every 30 hours at ~12,500 miles away.
  • Both are likely captured asteroids, are heavily cratered, and were discovered by Asaph Hall in 1877.
  • Mars’ moons transit the Sun, creating a phenomenon similar to the solar eclipses we see on Earth. But because Mars’ moons are so small and irregular in shape, they do not fully cover the solar disk or reveal the Sun’s corona.
water on Mars

Water on Mars

  • Scientists believe that 4 billion years ago, Mars had enough water to cover its entire surface to a depth of 140 miles!
  • Most water today is locked up as ice, primarily at the polar caps (with a seasonal layer of CO₂).
  • Recurring slope lineae (RSL) hint at possible seasonal briny (salt) water flows.
Mars Atmosphere

Atmosphere

  • Very thin, mostly CO₂ (~95%), with small amounts of nitrogen and argon.
  • Atmospheric pressure is less than 1% of Earth’s.
  • Temperatures range from ~70s °F (20s °C) near the equator to -225 °F (-153 °C) at the poles.
  • Due to a phenomenon called Mie scattering, which affects how fine dust scatters light, Martian sunsets appear blue, not red.
Mars Clouds

Clouds

  • Some thin, cirrus-like, water ice clouds are present.
  • CO₂ ice clouds form at high altitudes under extremely cold conditions.
  • Dust clouds occur when warm air rises, cools, and then sinks, carrying dust.
Martian Dust Storm

Martian Dust Storms

  • Frequent; some become “global dust storms” lasting for weeks, obscuring surface features.
Martian Dust Devils

Martian Dust Devils

  • Similar to Earth’s but can be larger (up to 8 km high).
  • Have been known both to threaten and to clean rover solar panels.

 

Human Exploration and the Future of Mars

Exploration

We hope this guide helped you get better acquainted with the Red Planet. As you observe Mars, remember that rovers originally from Earth are currently exploring its dusty plains, while orbiters circle overhead.

Indeed, Mars is one of the most thoroughly explored planets. Since 1965, missions like Mariner 4, Viking 1 & 2, Pathfinder/Sojourner, Mars Global Surveyor, Spirit & Opportunity, Mars Reconnaissance Orbiter, Curiosity, InSight, Perseverance & Ingenuity, Tianwen-1, and the Hope Orbiter have significantly advanced our understanding of this intriguing world.

With future human missions, Mars may soon reveal even more of its long-held secrets. Will it confirm evidence of past (or present) life? Only time will tell. Until then, enjoy your journey exploring Mars—from your backyard or anywhere else under clear skies!

 

 

 

Other articles you might be interested in: Ultimate Guide to Observing the Universe