Magnitude scale: lower magnitude Þ brighter e.g., a mag. 1 star is brighter than a mag. 2 star, a mag. -1 star is brighter than a mag. 0 star. Magnitude is a measurement of light intensity (energy per unit time per unit area) log scale: Each magnitude differs by an intensity ratio of about 2.512 e.g., a mag. 1 star is 2.512 times brighter than a mag. 2 star a mag. 2 star is 2.512´2.512 times brighter than a mag. 4 star \ a difference of 5 mag. = 2.5125 = 100 times in intensity Fig. 2-8 The scale of apparent visual magnitudes extends into negative numbers to represent the brighter objects. The sun has an apparent magnitude of about -27; it is the brightest celestial object as seen from the earth. Apparent magnitude: magnitude as measured on the earth (Fig. 2-8) Closer objects look brighter, and farther objects look dimmer, e.g.,  a close candle may appear brighter than a far street lamp. apparent magnitude does not give a measure of the intrinsic brightness It only measures the apparent brightness of a body (the amount of light energy received on Earth). Absolute magnitude: Magnitude as if all stellar objects were placed at the same distance from the earth. It measures the intrinsic brightness of a celestial body (the amount of light energy emitted by the body).