What systematic observational method did William Herschel employ to attempt charting the structure of the Milky Way?

Answer

Star gauging

William Herschel dedicated himself to charting the heavens by counting stars in specific, small patches, a technique known as 'star gauging,' assuming star density varied depending on the direction observed.

What systematic observational method did William Herschel employ to attempt charting the structure of the Milky Way?
astronomytheorystarMilky Way