Free Astronomy Magazine September-October 2026

43 SEPTEMBER-OCTOBER 2026 ASTRO PUBLISHING T his artist’s concept out- lines the areas of the galactic core covered by Eu- clid (orange) and the future survey area of the Roman telescope (yellow). The Eu- clid observations more than cover Roman’s planned sur- vey area because the Ro- man coverage wasn’t yet set in stone when Euclid imaged the area. The only exception is the portion right in the galactic center since Euclid’s visible light observations can’t pierce the thick dust in this region like Roman’s infrared vi- sion will. [NASA’s Goddard Space Flight Center] detail Roman will see, it has similar resolution and covers a larger re- gion — about 5 square degrees, or the sky area covered by about 25 full moons — since Roman’s survey area hadn’t yet been determined when the observation took place in March 2025. Over the course of its five-year pri- mary mission, Roman will repeat- edly image a smaller region (1.7 square degrees, or roughly the sky area covered by 8.5 full moons) to watch how hundreds of millions of stars and other objects change over short time periods. Monitoring these changes will reveal hordes of new planets, along with many other cos- T his image from the Advanced Camera for Surveys instrument on NASA’s Hubble Space Telescope is part of a 1.1-square-degree survey of the center of the Milky Way. Hub- ble’s full survey, which is made up of more than 350 individual images taken across about 14 months, is smaller but higher resolution than ESA’s Euclid observations and both overlap with the area Roman will cover. By capturing preview images years before Roman begins its mi- crolensing search, Hubble and Euclid provide early reference points that will help astronomers measure the motions of stars and better charac- terize the planets and other objects Roman discovers. [Adapted from Terry et al. 2026]