Formulae. 1  Eclipsing binary: diameter = speed Ã time of eclipse. 2  Size from luminosity: star's radius/Sun's radius = (Sun's temperature/star's temperature)2 Sqrt[star's luminosity/Sun's luminosity].
MOA is a mathmatical concept that most firearm scopes incorporate. Minute of Angle (MOA) is critical to sighting in your scope. MOA mathematical concepts were used to develop the AccuScope scope sighting reference tool. The only MOA information needed to use AccuScope is your scope's MOA number.
Aimpoint series sights feature either a 4 MOA dot or a 2 MOA dot. MOA stands for minutes of angle and 1 MOA = 1at 100 yards = 3 cm at 100 meters. If you have a 4 MOA, this means that the dot is about 12 cm at 100 m (4 at 100 yards), 6 cm at 50 m and 3 cm at 25m.