Astronomy Picture of the Day (APOD) — a project that publishes daily images and photographs of space with brief explanations from professional astronomers — has announced material for October 28, 2026, dedicated to the mutual occultation of two Jupiter moons: Ganymede and Io. This phenomenon occurs when one moon passes in front of another from the observer's perspective, temporarily obscuring it. Ganymede is the largest moon in the Solar System, exceeding the planet Mercury in size, possesses its own magnetosphere, and presumably has a subsurface ocean. Io, for its part, is known as the most volcanically active body in the Solar System — its surface is constantly transformed by eruptions caused by the tidal effects of Jupiter's gravity. Mutual occultations of the giant moons of a planet are observed comparatively rarely and are of interest to both professional astronomers and amateur astrophotography enthusiasts. Such events allow for refining the orbital parameters of moons and studying the dynamics of the Jupiter system. The APOD project is supported by NASA and Michigan Technological University and is one of the oldest and most popular science communication astronomy resources on the internet. In addition to daily publications, the website offers an image archive, educational materials, and the opportunity to discuss the featured images.