Star magnitudes

The Greek astronomer Hipparchus looked at the heavens in antiquity and noticed that the stars were not equally bright to the naked eye. He reckoned that there were 6 levels of brightness, which turns out to the about right. He called the brightest stars magnitude 1 and the dimmest magnitude 6. On the picture of Cygnus shown, the two bigger dots are about magnitude 2 and the one at the bottom of the wing is magnitude 3. Deneb has been cut off this diagram and is magnitude 1. The modern system can use measuring instruments not eyes so is more precise and awards decimal places as well. Of course, these are apparent magnitudes because they show what it looks like. Some dim stars seem bright because they are close and some bright stars seem dim because they are distant. Scientists ahve been able to work out bright stars actually are and have calculated the absolute magnitude to compensate for this problem.