Fresh from the excitement of Monday’s Wolf Moon, there’s another treat in store for sky-watchers this week, with Mars appearing large and bright in the sky.
In the early hours of Thursday morning, Mars will be “in opposition” to Earth, which means that the planet will be lit up by the Sun’s rays and appear large and bright – meaning star-gazers can get extra clear views through telescopes or even with the naked eye.
Due to its wonky elliptical orbit, a ‘Mars opposition’ happens roughly every 27 months, and offers the best view of the Red Planet.
What is Mars opposition?
Mars will reach ‘opposition’ with Earth on Thursday, meaning that Mars is on the opposite side of Earth from the Sun, with the three essentially forming a ‘line’ in Space.
During opposition, Mars catches the full glare of the Sun as seen from Earth.
This means that amateur astronomers with backyard telescopes will be able to get a clear view of surface features on Mars, from the canyons of Valles Marineris to the largest volcano in the solar system, Olympus Mons.
Opposition offers a chance for both amateur astronomers and professional telescopes to capture images of Mars, as shown in this Hubble image (Hubble Space Telescope/NASA)
Sky watchers will see Mars rising in the east at sunset and setting in the west at sunrise.
Planetary oppositions for planets such as Jupiter and Uranus are near-annual, but the difference between Earth and Mars’s orbits (Mars orbits the sun every 687 days) means that Mars opposition is less frequent.
What’s special about this year’s?
Mars will be less bright this year than it sometimes is at opposition – with this year not a ‘perihelic opposition’.
In a perihelic opposition, Mars is close to Earth while also at its closest point to the Sun, meaning it appears even larger and brighter.
The last perihelic opposition was in 2018 and the next one will not be until 2033, with perihelic oppositions occurring roughly every 15 to 17 years.
When will the opposition happen?
The best time to see this week’s opposition in the UK will be on Thursday 16 January at 1.17am.
Mars made its closest approach to Earth since 2022 on Sunday, and will enter opposition on Thursday.
The Red Planet will be more visible throughout the rest of the year, until it becomes lost in the sun’s glare in November 2025, says Space.com.
Mars will next enter opposition on 19 February 2027.
How can I see Mars this week?
Mars will rise at sunset and be visible above and to the right of the moon, in the constellation Gemini.
It might be visible to the naked eye, depending on weather, but a telescope or binoculars will offer a clearer view.
The Sky at Night Magazine recommends using a 75mm telescope or larger.