How did space photography astronomers

The earliest known photograph of an astronomical object, the Moon, was made by J. W. Draper in 1840. This was followed five years later by Foucault and Fizeau photographing the Sun from Paris. These early photographs were made using the daguerreotype process, a difficult and slow method using silver-coated copper plates. The long exposure times of about one minute required even for portrait photographs meant that any astronomical use was limited to only the very brightest objects.