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AA+ v1.90

July 30, 2017

Just to let everyone know that v1.90 of AA+ has been released. Updates for this version include:

  • AA+ now includes complete support for the ELP/MPP02 theory (ftp://cyrano-se.obspm.fr/pub/2_lunar_solutions/2_elpmpp02/) in addition to the ELP2000-82B theory (http://cdsweb.u-strasbg.fr/cgi-bin/qcat?VI/79/) and truncated ELP2000 theory as presented in Meeus’s book. This theory is the most up to date version of the ELP Lunar theory. It includes fits to the JPL Ephemerides of DE405 & DE406, LLR (Lunar Laser Ranging) as well as the Nominal model used in ELP/MPP02. The full ELP/MPP02 theory is implemented by the new AAELPMPP02.cpp/h files included in the AA+ download. This new class in AA+ to support ELP/MPP02 has been machine generated by parsing the ELP/MPP02 files with a custom C++ app to generate the new header and source modules. The results have been comprehensively spot checked against the ELP/MPP02 test values provided in the ELP/MPP02 files. The AA+ implementation is based in part on a C# implementation of the theory at https://sourceforge.net/projects/astromony/files/ as well as a C implementation in GAL (General Astrodynamics Library) by Paul Willmott at http://www.amsat-bda.org/GAL_Home.html. Similar to the ELP2000-82b theory the results are returned in the equator and equinox of J2000. Client code is free to use the CAAPrecession class to precess the coordinates to the required reference frame. Please note that if you want to compile AA+ to not pull in a dependency on the new and quite large ELP/MPP02 module, then you can define the preprocessor value "AAPLUS_NO_ELPMPP02" in your project. With this addition AA+ is now 27.7 Megabytes and 377 thousand lines of C++ source code. Testing shows the time taken to call CAAELP2000::EclipticRectangularCoordinatesJ2000 on my 3.2GHz Core i7 processor is about c. 1ms while the call to the new CAAELPMPP02::EclipticRectangularCoordinatesJ2000 method including returning the derivatives takes c. 5ms. From the ELP/MPP02 paper, the longitude and latitude is three times more accurate than ELP200-82B and the distance is eight times more accurate. For the interval +1950 to +2060, there is reported accuracy of 0.06 arc seconds in longitude, 0.003 arc seconds in latitude and 4 meters in distance.
  • Updated the observed DeltaT values from http://maia.usno.navy.mil/ser7/deltat.data to 1st June 2017.
  • Updated the predicted DeltaT values from http://maia.usno.navy.mil/ser7/deltat.preds to Jan 2026.
  • Removed unnecessary SECOND_2_RAD define in AAELP2000.cpp module.
  • Updated various CAAELP2000 methods to use "const" parameters.
Categories: Web Site Updates
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