Defunct first-party. 1  Aces Studio â Microsoft Flight Simulator series. 2  Digital Anvil â Brute Force, Freelancer. 3  Ensemble Studios â Age of Empires series, Halo Wars. 4  FASA Studio â MechWarrior series, Shadowrun. 5  Hired Gun â Halo 2 for Windows Vista. 6  Lionhead Studios â Fable series, Black & White series.
The term meridiangenerally refers to any line that runs pole to pole, on the surface of a sphere. Figure 2a (left): The Earth's coordinate system, latitude and longitude. The central axis runs through the North and South poles. Figure 2b (right): The pole-to-pole lines along the surface are lines of longitude.
The earth's axis is the axis about which the celestial sphere appears to rotate. The extensions of the earth's axis through the north pole (NP) and south pole (SP) of the Earth intersect with the north celestial pole (NCP) and the south celestial pole (SCP), respectively. The projection of the Earth's equator on the celestial sphere defines the celestial equator (CE).