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Geodetic astronomy

From Wikipedia, the free encyclopedia

Geodetic astronomy or astronomical geodesy (astro-geodesy) is the application of astronomical methods into geodetic networks and other technical projects of geodesy.

Applications

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The most important applications are:

Measuring techniques

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Important measuring techniques are:

The accuracy of these methods depends on the instrument and its spectral wavelength, the measuring or scanning method, the time amount (versus economy), the atmospheric situation, the stability of the surface resp. the satellite, on mechanical and temperature effects to the instrument, on the experience and skill of the observer, and on the accuracy of the physical-mathematical models. Changing weather or atmospheric conditions near the observation site can negatively affect atmospheric refraction in the zenithal direction, referred to as anomalous or zenithal refraction; anomalous refraction is considered to be the primary source of error in geodetic astronomy deflection data.[1]

Therefore, the accuracy reaches from 60" (navigation, ~1 mile) to 0,001" and better (a few cm; satellites, VLBI), e.g.:

Astrogeodetic leveling is a local geoid determination method based on vertical deflection measurements.[2] Given a starting value at one point, determining the geoid undulations for an area becomes a matter for simple integration of vertical deflection, as it represents the horizontal spatial gradient of the geoid undulation.[3][4]

See also

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References

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  1. ^ Hirt, Christian; Bürki, Beat (2006). "Status of Geodetic Astronomy at the Beginning of the 21st Century" (PDF). Geodäsie und Geoinformatik der Universität Hannover (258): 81–99. Retrieved 1 June 2025.
  2. ^ "Geoid Evaluation". National Geodetic Survey. NOAA. 2024. Retrieved 1 June 2025.
  3. ^ Jekeli, Christopher; Kwon, Jay H. (October 2002). "Geoid profile determination by direct integration of GPS inertial navigation system vector gravimetry". Solid Earth. 107 (B10): ETG 3-1–ETC 3-10. doi:10.1029/2001JB001626.
  4. ^ "Deflection of the vertical". UNTERM. United Nations. Retrieved 1 June 2025.
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