Which African capital lies closest to the Greenwich Meridian?
Prime meridian (Greenwich) to use the Paris meridian for several decades. In the 18th century, London lexicographer Malachy Postlethwayt published his African maps showing the "Meridian of London" intersecting the Equator a few degrees west of the later meridian and Accra, Ghana. The plane of the prime meridian is parallel to the local gravity vector at the Airy transit circle () of the Greenwich observatory. The prime meridian was therefore long symbolised by a brass strip in the courtyard, now replaced by stainless steel, and since 16 December 1999, it has been marked by a powerful green laser shining north across the London
Prime meridian (Greenwich) Greenwich prime meridian and the plane passing through the Earth's rotation axis on the ITRF zero meridian are effectively parallel. However, the claim, found, e.g., in a BBC article that this difference between astronomical and geodetic coordinates means that any measurements of transit time across the IRTF zero meridian will occur 0.352 seconds (or 0.353 sidereal seconds) before the transit across the "intended meridian" is based on a failure of understanding. The explanation by Malys et al. on the other hand is both lucid and correct. As of 2018 the Greenwich meridian passes through: Prime meridian (Greenwich) A prime meridian,