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information_for_astronomers:user_guide:antenna
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information_for_astronomers:user_guide:antenna [2017/04/04 14:10] akraus |
information_for_astronomers:user_guide:antenna [2022/03/25 08:27] akraus |
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| Latitude 50°31'29.4" North (50.52483°); | Latitude 50°31'29.4" North (50.52483°); | ||
| </code> | </code> | ||
| - | the Altitude (track level/elevation axis) is 367/417m. These positions are based on | + | the Altitude (elevation axis = reference point) is 416.825 m (height over the reference ellipsoid). These positions are based on |
| - | [[http://www.ccivs.bkg.bund.de/EN/Quarterly/VTRF-Results/VTRF-Stations/vtrf-stations_node.html|observations]] of the | + | [[https://www.ccivs.bkg.bund.de/index.php?uri=quarterly/stationcoordinates/xyz|geodetic VLBI observations]] of the |
| - | [[http://ivscc.bkg.bund.de|Internation VLBI Service for Geodesy & Astrometry (IVS)]] | + | [[http://ivscc.bkg.bund.de|Internation VLBI Service for Geodesy & Astrometry (IVS)]]. The cartesian coordinates |
| + | <code> | ||
| + | x = 4033947.225142 m | ||
| + | y = 486990.906449 m | ||
| + | z = 4900431.141999 m (as of May 2019) | ||
| + | </code> | ||
| + | are have been used to determine the geographic coordinates above | ||
| (Reference frame is the Earth ellipsoid defined by [[http://en.wikipedia.org/wiki/World_Geodetic_System|WGS84]]). | (Reference frame is the Earth ellipsoid defined by [[http://en.wikipedia.org/wiki/World_Geodetic_System|WGS84]]). | ||
| + | Note, that these values correspond to the cross-section of the azimuth and elevation axis (i.e., the height of the | ||
| + | elevation axis given above). That's the reference point ("geodetic point") of the antenna.\\ | ||
| + | The corresponding track level height is 366.8 m. | ||
| + | |||
| + | For some purposes, the height with respect to the [[https://en.wikipedia.org/wiki/Geoid|Geoid]] (i.e. "above mean sea level") is relevant. There are different models for the Earth gravitational field (which defines the amsl level), e.g., [[https://en.wikipedia.org/wiki/EGM96|EGM96]] or [[http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/egm08_wgs84.html|EGM2008]]. In Germany, also the [[https://de.wikipedia.org/wiki/Deutsches_Haupth%C3%B6hennetz|DHHN2012]] model is in use (sometimes also the older DHHN92). The latter is the basis for most topographic map material of the area. On the other hand, [[https://en.wikipedia.org/wiki/Shuttle_Radar_Topography_Mission|SRTM]] data are with respect to the EGM96 Geoid. | ||
| + | |||
| + | With these models, the following heights can be derived | ||
| + | |||
| + | ^Model^Correction w.r.t. WGS84 ellipsoid^Elevation axis height (amsl)^Track level height (amsl)^ | ||
| + | |EGM96 | -48.0586 | 368.6445 | 318.6445 | | ||
| + | |EGM2008 | -47.5935 | 369.1096 | 319.1096 | | ||
| + | |DHHN2012 | -47.698 | 369.0051 | 319.0051 | | ||
| + | (Based on results with online calculators from [[http://gibs.bkg.bund.de/geoid/gscomp.php?p=g|BKG]] and [[https://geographiclib.sourceforge.io/cgi-bin/GeoidEval|geographiclib]]) | ||
| == Axis limits / Cable wrap == | == Axis limits / Cable wrap == | ||
| The Effelsberg telescope has an altazimuth-mount, with the limits:\\ | The Effelsberg telescope has an altazimuth-mount, with the limits:\\ | ||
| - | 33.5° ≤ Azi ≤ 503° (0° is North, 90° East)\\ | + | 33.5° ≤ Azi ≤ 503° (i.e., 360° + 143° - there is an overleap in the East, 0° is North, 90° East)\\ |
| 8.1° ≤ Elv ≤ 89°\\ | 8.1° ≤ Elv ≤ 89°\\ | ||
information_for_astronomers/user_guide/antenna.txt · Last modified: 2022/03/28 12:09 by akraus
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