Starwatch: Mars and Regulus will make for an eye-catching pair

This week, stargazers have the opportunity to witness a striking conjunction of Mars and Regulus, the brightest star in the constellation Leo. Observers looking to the western sky will find these two celestial bodies remarkably close, separated by less than one degree, which is less than twice the apparent diameter of the full moon. This proximity makes them easily visible to the naked eye and allows them to fit within the same field of view when viewed through binoculars. However, as the week progresses, Mars and Regulus will gradually move further apart, so interested observers are encouraged to take note of their conjunction around 2300 BST on 16 June 2025, particularly from locations such as London, where the celestial display can be best appreciated.

The visual contrast between Mars and Regulus will be particularly notable due to their differing colors. Mars will appear as a reddish hue, while Regulus will shine with a blue-white light. Regulus is an impressive star, ranking as the 21st brightest in the night sky, located approximately 79 light years from Earth. It possesses over four times the mass of the sun and has a diameter that is also more than four times larger, emitting around 340 times the energy produced by the sun. In addition to the conjunction of Mars and Regulus, observers in the southern hemisphere will also have the chance to see this event in the north-northwest sky. Furthermore, on 19 June, the moon will be positioned near Saturn in the constellation Pisces, offering additional opportunities for celestial observation during this period.