ASTRONOMICAL AZIMUTHS FOR LOCAL CONTROL

ASTRONOMICAL AZIMUTHS ARE USED FOR CONTROLLING LOCAL SURVEYS IN LARGE AREAS OF THE UNITED STATES WITHOUT FIRST OBSERVING ASTRONOMICAL LONGITUDES. NORMALLY, ASTRONOMICAL LONGITUDE IS USED TO OBTAIN THE LAPLACE CORRECTION FOR CHANGING AN ASTRONOMICAL AZIMUTH INTO A GEODETIC AZIMUTH. WHEN GEODETIC AZIMUTHS ARE NOT EASILY AVAILABLE FOR CONTROLLING TRAVERSES OR OTHER SURVEYS, AN ASTRONOMICAL AZIMUTH MAY BE OBSERVED AND THE COAST AND GEODETIC SURVEY MAY BE REQUESTED TO FURNISH AN INTERPOLATED LAPLACE CORRECTION. THIS CORRECTION MAY THEN BE ADDED TO THE ASTRONOMICAL AZIMUTH TO OBTAIN A GEODETIC AZIMUTH. IN FIRST- ORDER SURVEYING, A FIRST-ORDER LONGITUDE IS STILL REQUIRED, IN SECOND-ORDER WORK, HOWEVER, THESE INTERPOLATED CORRECTIONS ARE USUALLY OF SUFFICIENT ACCURACY. METHODS FOR OBSERVING THE AZIMUTH ARE DISCUSSED AS WELL AS THE LAPLACE CORRECTIONS. A MORE WIDESPREAD USE OF ASTRONOMICAL AZIMUTH CAN CONTRIBUTE TO IMPROVED CONTROL THROUGH THE APPLICATION OF INTERPOLATED CORRECTIONS. THIS ELIMINATES SECOND-ORDER LONGITUDE DETERMINATIONS WHICH REQUIRE EXTREME CARE AND EXACT TIMING. IF THE PERSONAL EQUATION OF THE OBSERVER IS NOT DETERMINED AT A FIRST-ORDER ASTRONOMIC STATION, THIS ERROR ALONE COULD PROBABLY BE AS GREAT AS THE LAPLACE CORRECTION ITSELF.

  • Supplemental Notes:
    • Vol 27, No 4, PP 645-648, 3 FIG
  • Authors:
    • Poling, A A
  • Publication Date: 1967-12

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00202633
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 12 1994 12:00AM