Atmospheric Refraction and Building a Local Observational Model

A new application of the astronomical atmospheric refraction in space geodesy is introduced in this paper.To meet with high requirement of the application,it is necessary to develop an effective method for directly measuring instantaneous atmospheric refraction and constructing an atmospheric refraction model adapted to the geographical environment around the observing station.Necessary conditions for determining the refraction values are listed in brief.Making use of structural characteristics of the Lower Latitude Meridian Circle and the error theory of this instrument,we have developed a method used to measure directly instantaneous atmospheric refraction,and moreover built a local observational astronomical re fraction model toward the east,south,west and north of Yunnan observatory that is classified according to the star's spectral type.