Most of the discoveries astronomers have made about the universe needed light measurements to confirm or suggest theories. There are all kinds of instruments astronomers use to make measurements of star brightness. We call these measurements photometric data. Photometric means light-measuring. Your eyes are your instruments You are going to use your own eyes and a special technique for making photometric measurements.
Interpolation is a word scientists use when a measurement is estimated between two known values.
Making a brightness estimate is easy in theory but requires some practice. We call the measurement of brightness the star s magnitude. How to find a variable star If you do not have the W Cyg chart in front of you, please click on the image and print one out now. This chart is for W Cygni, a star you can find with binoculars from your own yard. But first let s try a simple lesson in interpolation and using star charts.