The degree of brightness of an object in the sky according to a scale on which the brightest star has a magnitude -1.4 and the faintest visible star has magnitude 6. Sometimes referred to as apparent magnitude. In this scale, each number is 2.5 times the brightness of the previous number. Thus a star with a magnitude of 1 is 100 times brighter than on with a visual magnitude of 6.
A measure of the total amount of matter contained within an object
החצובה עליה רוכב הטלסקופ. ראה הרחבה במאמר לבחירת טלסקופ.