A measure of the extent of an eclipse. In a solar eclipse, the magnitude is the fraction of the Sun's diameter that is covered by the Moon. If the eclipse is total, magnitude is replaced by the ratio of the apparent diameters of the Moon and Sun, which is always 1.00 or more during totality. The magnitude of a lunar eclipse is the fraction of the Moon's diameter covered by the Earth's umbra; at a total eclipse it can be much larger than 1.00 (or 100%) because the Earth's shadow is much larger than the Moon. Eclipse magnitudes are expressed either as a decimal or as a percentage; the magnitude of a partial eclipse may be denoted as, for example, 0.59 or 59 %.
Subjects: Astronomy and Astrophysics.