Sky & Telescope September 2025 Magazine

Radio Array Retrofit, Swimming with Delphinus, and the Great Comet of 1680

In the September 2025 issue of Sky & Telescope, we feature the Atacama Large Millimeter/submillimeter Array (ALMA)’s new face lift. This update will allow the radio array to observe at even more wavelengths and record more data. Meanwhile, the Euclid space telescope has released its first images with many more to come as it prepares to complete a gigantic 3D map of the universe’s structure. Back here on Earth, we’re taking a peek at the deep-sky objects hidden in a very small portion of the sky: Delphinus, the Dolphin. Or if you’re more of a daytime observer, we have a DIY project that’s right up your alley: Richard Schrantz guides us on how to build our own spectroheliograph at home.