The Red Planet will next reach opposition on July 27-28, 2018, and it will be a fine sight in a telescope for the 2-3 months before and after this date. The planet reaches opposition in the constellation Capricorn, east of Sagittarius, so it’s quite far south along the ecliptic during this apparition. At the end of July, the planet is a very bright magnitude -2.8, almost as bright as it ever gets, and its disk spans 24″. This is the best apparition of the planet since the historically close and bright opposition of 2003.
Here’s a complete guide to the planet Mars and tips on how to observe it during its next apparition.