title: 'What is FWHM?' Subtitle: 'Full Width Half Maximum is a statistical measurement of some thing. But what does it mean for Astrophotography and are high numbers good or low numbers?'

What is FWHM?

Full Width Half Maximum is the measurement of a thing on a graph such that the FWHM number is the "width" of the graph when the left and right sides of the graph are at "half" the "maximum" value of the graph. Perhaps a chart will help, courtesy of Wikipedia.