Leo in Astronomy
The Lion (also Great Lion, Leo major) is one of the constellations of the Zodiac. It comprises 77 stars that are visible to the 'unarmed' human eye.
The brightest is Regulus (='Little King') at 85 light-years from Earth, the second brightest Denebola at 42 light-years. Eta Leonis, north from Regulus, looks weak, but it spreads a hundred times as much light as Regulus. This star is at a much greater distance from Earth: 1700 light-years.
In the constellation of Lion and in its surroundings astronomers find a large number of galaxies like M65 and M66. Both have a beautiful spiral-form. They are at a distance of 20 million light-years.
The constellation of Lion was already mentioned in the famous Almagest of the Egyptian astronomer Ptolemaios. Copernicus gave Regulus its name during the Fifteenth Century.
A second lion-constellation is Little Lion (Leo minor), introduced around 1670 by the German astronomer Hevelius. Leo Minor can be found between Great Lion and Great Bear. This constellation consists of 24 visible stars, but no particular bright ones.
Leo in Astrology
(For those who believe in it)
Leo is the fifth constellation of the Zodiac. Between July 21 and August 21 the Sun is in the constellation of Lion. Astrologers say about the astrological Lion:
Lions are often leaders and they expect unconditional obedience from other people, which they mostly get because of their innate talent for leadership. Often a Lion is in the center of power and he doesn't tolerate that others resist his position. The Lion is an honest and righteous leader, who rises against injustice. He also wants justice from other people and when they disappoint him, then he will mourn that deeply.
Lionesses are strong personalities too. They do not like to live under other people's authority. They respect authorities, but they do not lose their self respect and they won't make themselves subordinate. Lionesses are very skillfull in delegating tasks.