Urdhvamadho apara poorvamihaadyam praahuridam samamandala manyath

thadvadihotthara dakshinadikstham vrutthayugam vidisorapi thadvath

  Vertical circle passing through the west and east cardinal points is the first circle: this is called the samamandala. (This circle is the prime vertical. Another similar vertical circle (called the yaamyottara-vrutta) which passes through the north and south cardinal points is called the meridian.]]>