trillion pixels, and makes up a petabyte of data — a thousand terabytes, or a million gigabytes. Oh, it also has over a billion galaxies in it. A. Billion. Like I said: Vast. It's the result of the DESI Legacy Imaging Surveys, maps of the sky made by the three observatories (the Dark Energy Camera Legacy Survey, the Beijing-Arizona Sky Survey, and the Mayall zband Legacy Survey, in combination with the orbiting WISE infrared observatory). They mapped the northern sky in seven colors, covering a third of the entire sky — 14,000 square degrees, or the equivalent area of 70,000 full Moons on the sky.