New Zodiac Sign Dates, In astronomy, the zodiac is the ring of constellations that the lines of the ecliptic are the apparent paths of Sun in the celestial sphere during the year? The paths of the Moon and planets are also roughly in the ecliptic, and therefore are also within the constellations of the zodiac. In astrology, zodiac signs means those that divide the ecliptic into twelve equal zones of celestial longitude.
As such, the zodiac is a celestial coordinate system, or more precisely an ecliptic coordinate system, taking the ecliptic latitude of the origin and the position of the sun at the vernal equinox as to the origin of longitude.
It is known to have been used in Roman times, based on concepts inherited by astronomy Hellenistic astronomy Babylonian Chaldean period (mid-first millennium BC), which, in turn, derived from a old system of lists of stars along the ecliptic.  The construction of the zodiac is described in the Almagest of Ptolemy (2nd century AD).
The term derives from the Latin zodiac z? Diacus, which in turn comes from the Greek (Z? Kuklos Diakos), which means “circle of animals”, (Z? Dion), short for?? (Z? On) “animal”. The name is motivated by the fact that half of the classical Greek zodiac animals are represented as (in addition to two mythological hybrids).
Although the Zodiac remains the basis of the ecliptic coordinate system used in astronomy, in addition to the equatorial, the duration and the names of the twelve signs are now often associated with astrology horoscope.
Tropical Zodiac Symbol Name
(2011 UTC) sidereal zodiac
(Jyotisha) (2011 UTC)  The name of the IAU constellation boundaries (2011) Solar stay brighter
Aries March 20-April 20 April 14 – May 1 Aries April 19 to May 14th Hamal 25.5 days
Taurus April 20 to May 21 May 14 – June 1 Taurus May 14 – June 21 38.2 days Aldebaran
Gemini May 21 – June 21 June 14-July 31 Gemini June 21 – July 21 29.3 days Pollux
Cancer June 21-July 23 July 14 to August 1 cancer July 21 to August 11 21.1 days Al Tarf
Leo July 23 to August 23 August 14-September 31 Leo August 11 – September 17 36.9 days Regulus
Virgo August 23-September 23 September 13 to October 30 Virgo September 17 – October 31 44.5 days Spica
Libra September 23 to October 23 October 14-November 31 Libra October 31 – November 21 21.1 days Zubeneschamali
Scorpio October 23-November 22 November 13-December 30 Scorpio November 21 – November 30 Antares 8.4 days
Ophiuchus n / a Ophiuchus November 30 to December 18 Rasalhague 18.4 days / Alpha Ophiuchi
Sagittarius November 22-December 22 December 14 – 2 Janvier Sagittarius December 18 to January 21 Kaus Australis 33.6 days
Capricorn December 22-January 20 January 13 to February 1 Capricorn January 21 – February 17 27.4 days Deneb Algedi
Aquarius January 20 to February 19 February 12 to March 2 February 17 Aquarius – March 12 23.9 days Sadalsuud
Pisces 19 February to 20 March 14 March – 1 April 12 March Pisces – April 19 37.7 days Eta piscium