Astrogeodetic Deflections of the Vertical from Stars Observations with the Danjon Astrolabe, or Similar Instruments

摘要

This report is a sequel to the report 'Basic Formulae for Determining the Computation of the Deflection of the Vertical from Astronomic Star Observations' (AD-A154 912). It addresses a new observational method that allows one to compute the astronomic zenith distance of the astrolabe instrument as a function of the time when the stars cross the almucantar of the astrolabe and their right ascension and declination, therefore independent of the astronomic station coordinates. The xi and eta deflection of the vertical components are obtained from an equation that relates the astronomic and geodetic zenith distance. The last is derived for each star as a function of the U.T. 1 time and geodetic latitude and longitude. Keywords: Deflection of the vertical, Vertex of isosceles triangles, Astrolabe observations, Latitude and longitude, Danjon Astrolabe, Astronomical observatories, and Navy.