Mars will soon become the biggest and brightest it has been since 2022 as it aligns with Earth and the sun on January 12, 2025. This alignment, known as opposition, provides the best opportunity to see Mars up close and observe its surface features.
Opposition occurs when Earth passes between Mars and the sun every 789 days, which is why it happens almost annually for planets like Jupiter and Saturn but not for Mars due to its relatively long orbit of about 687 Earth days. When this alignment happens, Mars appears at its closest point to Earth, making it easier to observe with telescopes or even just the naked eye.
During opposition, Mars will be shining brightly in the constellation Gemini and will appear as a bright, red point of light dominating the night sky. However, unlike some previous perihelic oppositions that can make Mars shine at an impressive magnitude, this 2025 alignment won’t be particularly impressive due to its relatively small disk size.
Despite not being the most spectacular event, the 2025 Mars opposition is still a great opportunity for astronomers and space enthusiasts to observe the Red Planet up close. NASA’s Escape and Plasma Acceleration and Dynamics Explorers (EscaPADE) mission, which was planned to launch in October 2024 but postponed to spring 2025, will take advantage of this alignment to study Mars’ real-time response to space weather.
While opposition occurs on January 12, 2025, the prime viewing window is actually from December 2024 through February 2025. This period offers the best conditions for observing Mars with good backyard telescopes or professional space-based telescopes. With a refractor telescope and a long focal length, astronomers can observe prominent features like Valles Marineris canyon systems, Olympus Mons volcano, and the planet’s southern polar ice cap.
The aftermath of the opposition will see Mars become less prominent in late November 2025 as it becomes lost in the sun’s glare. The next opposition won’t occur until February 19, 2027.
Source: https://www.space.com/stargazing/mars-opposition-2025-how-to-see-the-red-planet-at-its-biggest-and-brightest