An observing machine
DESI began collecting data in May 2021 and has far surpassed its original goals. The plan was to capture light from 34 million galaxies and quasars, extremely distant, bright objects powered by supermassive black holes, but the instrument instead observed more than 47 million galaxies and quasars, plus 20 million stars.
DESI is now pushing beyond its original mission, expanding its map of the universe into new and more challenging regions of the sky.
Through 2028, the survey will grow by about 20%, from 14,000 to 17,000 square degrees. For comparison, the Moon covers just 0.2 square degrees, while the full sky spans more than 41,000.
This expansion will take DESI closer to the crowded plane of the Milky Way, where bright nearby stars can obscure distant galaxies, and further to the south, where observations must peer through more of Earth’s atmosphere.