Board of Longitude chronometers, keeping) the time of the reference place when one is far away from it. For details of the efforts towards determining the longitude, see History of longitude. For many decades a sufficiently accurate chronometer was prohibitively expensive. The lunar distance method was used by mariners either in conjunction with or instead of the marine chronometer. However, with the expectation that accurate clocks would eventually become commonplace, John Harrison showed that his method was the way of the future. However the board, to its discredit, never awarded the prize to Harrison, nor anyone else. With the significant problems considered as
Celestial equator south), the celestial equator tilts towards the opposite horizon. The celestial equator is defined to be infinitely distant (since it is on the celestial sphere); thus, the ends of the semicircle always intersect the horizon due east and due west, regardless of the observer's position on Earth. (At the poles, the celestial equator coincides with the astronomical horizon.) At all latitudes, the celestial equator is a uniform arc or circle because the observer is only finitely far from the plane of the celestial equator, but infinitely far from the celestial equator itself. Astronomical objects near the celestial equator appear above