Spring Meridian is a part of the equinox meridiator that has the celestial longitude 0° (±0°) (0h). It is also called celestial Prime Meridian, First point of Aries Meridian, Pisces Meridian, March Meridian, Vernal Meridian, and Midnight Meridian because during the course of the year, the sun passes through this meridian on March 20 or 21 as it travels from southern to northern hemispheres and western to eastern hemispheres

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 along the ecliptic

Ecliptic

The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...

.

Unlike the geographical Prime Meridian

Prime Meridian

The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...

 on the world map

World map

A world map is a map of the surface of the Earth, which may be made using any of a number of different map projections. A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane....

, the Spring Meridian lies on both ends of the celestial map. But like Prime Meridian, it passes between poles

Celestial pole

The north and south celestial poles are the two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the imaginary rotating sphere of stars called the celestial sphere...

 and passes through the equator

Celestial equator

The celestial equator is a great circle on the imaginary celestial sphere, in the same plane as the Earth's equator. In other words, it is a projection of the terrestrial equator out into space...

. Like equator, Spring Meridian divides into two celestial hemispheres: western hemisphere to the west and eastern hemisphere to the east.

These constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

s are best visible in September because the sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 is furthest away from these constellations. There are following constellations passing through this meridian in order of decreasing declination

Declination

In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...

 (north to south).

• Ursa Minor
• Cepheus
  Cepheus (constellation)
  Cepheus is a constellation in the northern sky. It is named after Cepheus, King of Aethiopia in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
  
  
• Cassiopeia
  Cassiopeia (constellation)
  Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today...
  
  
• Andromeda
  Andromeda (constellation)
  Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...
  
  
• Pegasus
  Pegasus (constellation)
  Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
  
  
• Pisces
  Pisces (constellation)
  Pisces is a constellation of the zodiac. Its name is the Latin plural for fish, and its symbol is . It lies between Aquarius to the west and Aries to the east...
  
  
• Cetus
• Sculptor
  Sculptor (constellation)
  Sculptor is a small and faint constellation in the southern sky. It represents a sculptor. It was introduced by Nicolas Louis de Lacaille in the 18th century. He originally named it Apparatus Sculptoris , but the name was later shortened.-Notable features:No stars brighter than 3rd magnitude are...
  
  
• Phoenix
  Phoenix (constellation)
  Phoenix is a minor constellation in the southern sky. It is named after the Phoenix, a mythical bird. It is faint: there are only two stars in the whole constellation which are brighter than magnitude 5.0...
  
  
• Tucana
• Octans