Research on the Actual Measurement of Atmospheric Refraction

Low Latitude Meridian Circle(LLMC)will soon enter the period of testing and experiment. It is well kown that atmospheric refraction is the most important factor for astrometric observation. In order to get the high accuracy results, atmosphere refraction should be considered carefully. In the first part of this thesis paper, we have introduced the classic theories and processing mothods of the atmospheric refraction. At first, we have analyzed some important meteorological factors that may influence the value of atmospheric refraction in astronomy and argued the change of the atmospheric refraction accompanied with all kinds of conditions. Second, we have derived the formula and calculated the value of atmospheric refraction in two ideal atmosphere models and then presented the method of compiling atmospheric refraction table in astronomy. In the second part, we have analyzed the four conditions and explained that the classical theory can not fit for the conditions. Then we have introduced advantages of the LLMC and proved that the LLMC will be suitable for the four conditions very well. Finally we express the method and principle of actual measurement of atmospheric refraction and derive some formula.