Star Gazing – Useful Information

Glossary and Useful Formulae Magnification (Power) of telescopeĀ  = Focal length of telescope / Focal length of eyepiece Focal Ratio (f/stop) = Focal length of telescope / Aperture of telescope mirror or lensA “fast” speed (f/11, f/12 – f/15) is good for high power observing (moon, planets, splitting doubles)A “slow” speed (f/4, f/5) is good…