LEO

The constellation Leo
The constellation Leo.
Till Credner - Own work, AlltheSky.com,
CC BY-SA 3.0, wikimedia
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Map of the Leo constellation .
Copyright © 2003 Torsten Bronger.
It was created by Torsten Bronger using the program PP3 on 2003/08/18. At PP3's homepage, you also get the input scripts necessary for re-compiling the map.
The yellow dashed lines are constellation boundaries, the red dashed line is the ecliptic, and the shades of blue show Milky Way areas of different brightness.
The map contains all Messier objects, except for colliding ones. The underlying database contains all stars brighter than 6.5.
All coordinates refer to equinox 2000.0.The map is calculated with the equidistant azimuthal projection (the zenith being in the center of the image).
The north pole is to the top. The (horizontal) lines of equal declination are drawn for 0°, ±10°, ±20° etc. The lines of equal right ascension are drawn for all 24 hours.
Towards the rim there is a very slight magnification (and distortion)., CC BY-SA 3.0, wikimedia

Leo is a prominent constellation in spring. It is easily recognizable due to its many bright stars and distinctive shape. One can make out the crouching lion with its mane and shoulders forming ‘the sickle’, its chest pulsating with the Alpha star, Regulus, its paws poised to pounce and its tail shining brightly thanks to the Beta star Denebola. Leo’s tail used to include the constellation Coma Berenices.

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Leo in the Atlas Coelestis by John Flamsteed.
Jacopo Montano - Atlas Coelestis, John Flamsteed,
CC BY-SA 3.0, wikimedia

The story of Leo is tied to the story of Hercules. It refers to the Nemean lion which was killed by Hercules during the first of his twelve labors. Zeus commemorated this labor by placing the Lion in the sky.

Regolus is the Alpha star. It is very near the ecliptic and is thus hidden by the Moon and sometimes by the planets. In 2044 it will be eclipsed by the planet Venus. The star is a little less than 80 light-years from us and is 300 times brighter than the Sun.

The Gamma star Algieba is a magnificent double star which can be seen through a telescope of at least 100x magnification. The two stars rotate around a common center of mass in a period of a little more than 500 years. They are 126 light-years from the Solar System.

The Beta star Denebola is slightly dimmer than Algieba. It is a young star fairly near the Solar System at 36 light-years away and is 14 times brighter than the Sun. Its name, Deneb Alased, comes from Arabic and means ‘the lion’s tail’.
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The Leo 1 Galaxy is the dim area of light in the center. The brightest object is the Regulus star.
Scott AnttilaAnttler - Own work,
CC BY-SA 3.0, wikimedia

Leo is far from the Milky Way and is rich in extra-galactic objects. The nearest object is called Leo I and is next to the star Regulus. It is a little more than 800,000 light-years away and is thought to be a satellite galaxy of the Milky Way.

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The Leo Triplet.
Anttler at en.Wikipedia,
CC BY-SA 3.0, wikimedia

M 65 and M 66 are two galaxies which can be seen through telescopes. They are located in the back paw of Leo and together with NGC 3623 make up the well known Leo Triplet. M 65 is the closest object to us at about 22 million light-years. The other two objects are about 35 million light-years from Earth.

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NGC 2903.
Ole Nielsen - ngc7000.org,
CC BY-SA 2.5, wikimedia

Another spectacular galaxy is NGC 2903, a barred spiral galaxy similar to our Milky Way but smaller. It is a little more than 20 million light-years away.

Northern Hemisphere: Leo is visible in the early evening from January to the beginning of July. The best time to see the constellation is right after sunset in mid April when it is towards the south, nearer the zenith than the horizon.

Southern Hemisphere: Leo can be seen from February to June. At the southern middle latitudes, in April, right after sunset, we can find it high on the northern horizon.