The initial magnitude scale was established by Greek astronomer Hipparchus around 135 B.C.E., categorizing approximately 850 stars into six ranges from 1st (brightest) to 6th (faintest) magnitude.

You'll find this terrific open cluster midway between 5th-magnitude Sigma Cassiopeiae and 6th-magnitude Rho Cas. This group glows at magnitude 6.7, so even through a 4-inch telescope, you'll see 50 ...