A particular request for nighttime imagery that turned into a “systematic observation,” Crawford said, is Yellowstone National Park. The volcanic area’s 10,000 thermal features, such as geysers or hot springs or steam vents, can get hotter or colder, and they can appear or disappear.  Crawford is fascinated by volcanoes in general and recognizes the value of imaging them day and night. After Landsat 9 launched in 2021, when two satellites with the same high-quality sensors would together yield an image of each area of land every eight days, it seemed like a good time to start a consistent annual campaign to capture active volcanoes at night, he said.  R. Greg Vaughan of the USGS Astrogeology Science Center does field work at Yellowstone National Park. USGS photo R. Greg Vaughan of the USGS Astrogeology Science Center, who researches active volcanoes, gave him a list.…