V. sign of zodiac
Particulars:
General:
The fifth constellation of the zodiac. Its asterism, the Sickle, has the appeareance of an arched mane.
Stars and other objects
The brightest star of this constellation, alpha Leo,
called Regulus (meaning: the little king), is a
blue-white star (spectral type B7 V) of 1.35 mag. When viewed
with binoculars or small telescopes a wide companion of 8th mag
is revealed.
At the tip of the lion's tail the beautiful blue-white main
sequence star beta Leo, Denebola is
located. Viewed through a telescope beta Leo seems to have
an orange companion. But actually the two stars are far away from
each other.
Another optical double is tau Leo; the 7th mag campanion
of this orange 5th mag star can be seen in binoculars.
The binary gamma Leo, called Algieba (the
lion's mane), is a magnificent pair, which compenents consists of
a orange-red giant of 2.6 mag brightness and a yellow giant with
3.8 mag. A small telescope is sufficient to split gamma Leo
into the single stars. Using binoculars a unrelated 5th mag star,
40 Leo, can be seen next to them.
The binary omega Leo (a 7390) is a very difficult object
to resolve. You will at least need a scope with 250mm aperture.
The two stars revolve each other with a period of 117 years.
With very low power 54 Leo can easily be resolved into a
pair of 4.5 mag and 6.3 mag.
Between eta Leo and gamma Leo the double a 7704
can be found; but to resolve its components into single stars
(both are about 7.5 mag) telescopes of at least 100mm aperture
are required.
Zeta Leo is an optical triple star of 3.44 mag. Using
binoculars this stars seems to have two companions of 6th mag,
but they are not physically related together.
The red giant R Leo is a long period variabale star. Its
brightness variies from mag 4.4 to mag 11.6 (the Bright Stars
Catalog gives an average of 6th mag) with a period of about 313
days. It is located in the Lion's foreleg.
For Leo is located far away enough from the dust and the
starclouds of the Milky Way the farther away galaxies became
visible. There are some interesting galaxies in this region, but
they are not easy objects for small telescopes. The three
galaxies M65, M66 and NGC 3628 form a
conspicuous triple.
The other two Messier objects, M95 and M96 are two fainter spiral
galaxies. For more information and observing hints please follow
the links to the Messier database.
There is a large number of meteor showers assiciated with this
constellation. The most famous are the Leonids. This
shower radiates from the region of gamma Leo and can be
seen form November 14-20; the maximum can be observed on November
17th. Although the hourly rate from 10 to 15 meteor seems to be
small there is a cyclus of about 33 years with an enhanced
activity. The next spectacular storm is predicted to take place
in 1999.
The shower of the Alpha Leonids was first confirmed by
Radio Meteor Project. The duration of this shower cover the
period from January 13th to February 13th.
From February 14th to April 25th the Beta Leonids are
active. The maximum takes place around March 20th.
Nearly at the same time - from February 2nd to March 19th - the Delta
Leonids can be observed. The maximum of the activity peaks at
February 22nd.
A rather weak shower are the Gamma Leonids, which are
active from August 14th to September 12th with a maximum occuring
on August 25th.
The meteor shower of the Rho Leonids seems to be
non-existent; yet it has been discovered by radio studies in the
1960's. It seems to be "active" around March 14-15th.
The Sigma Leonids are another storm of doubt. Only one
observation has been made.
Detailed information for all meteor showers can be found in Gary
Kronk's database about meteor showers.
Mythological Background:
One of the twelve tasks of Hercules was to kill the lion, which this constellation is thought to represent.