Ryan Malloy
0544a78276
Phase 1 — Stars, comets, Keplerian propagation: - star_observe() / star_observe_safe(): fixed star alt/az via IAU 1976 precession, equatorial-to-horizontal transform - kepler_propagate(): two-body Keplerian orbit propagation for elliptic, parabolic, and hyperbolic orbits - comet_observe(): observe comets/asteroids from orbital elements - heliocentric type: ecliptic J2000 position (x, y, z in AU) Phase 2 — VSOP87 planets, ELP82B Moon, Sun: - planet_heliocentric(): VSOP87 heliocentric ecliptic J2000 positions for Mercury through Neptune (Bretagnon & Francou, MIT) - planet_observe(): full observation pipeline for any planet - sun_observe(): Sun position from negated Earth VSOP87 - moon_observe(): ELP2000-82B lunar position (Chapront-Touzé, MIT) - Clean-room precession (IAU 2006) and sidereal time (IERS 2010) - elliptic_to_rectangular utility (Stellarium, MIT) All Stellarium extractions are MIT-licensed, thread-safe (static caching removed for PARALLEL SAFE), zero external data files. All 9 regression tests pass (90ms total).
85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
/************************************************************************
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The code in this file is heavily inspired by the TASS17 and GUST86 theories
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found on
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ftp://ftp.imcce.fr/pub/ephem/satel
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I (Johannes Gajdosik) have just taken the Fortran code and data
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obtained from above and rearranged it into this piece of software.
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I can neither allow nor forbid the above theories.
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The copyright notice below covers just my work,
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that is the compilation of the data obtained from above
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into the software supplied in this file.
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Copyright (c) 2005 Johannes Gajdosik
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Permission is hereby granted, free of charge, to any person obtaining a
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copy of this software and associated documentation files (the "Software"),
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to deal in the Software without restriction, including without limitation
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the rights to use, copy, modify, merge, publish, distribute, sublicense,
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and/or sell copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included
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in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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****************************************************************/
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#ifndef ELLIPTIC_TO_RECTANGULAR_H
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#define ELLIPTIC_TO_RECTANGULAR_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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Given the orbital elements at some time t0 calculate the
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rectangular coordinates at time (t0+dt).
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mu = G*(m1+m2) .. gravitational constant of the two body problem
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a .. semi major axis
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n = mean motion = 2*M_PI/(orbit period)
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elem[0] .. either a (EllipticToRectangularA()) or n (EllipticToRectangularN())
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elem[1] .. L
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elem[2] .. K=e*cos(Omega+omega)
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elem[3] .. H=e*sin(Omega+omega)
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elem[4] .. Q=sin(i/2)*cos(Omega)
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elem[5] .. P=sin(i/2)*sin(Omega)
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Omega = longitude of ascending node
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omega = argument of pericenter
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L = mean longitude = Omega + omega + M
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M = mean anomaly
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i = inclination
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e = eccentricity
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Units are suspected to be: Julian days, AU, rad
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Results:
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xyz[0,1,2]=Position [AU]
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xyz[3,4,5]=Velocity [AU/d]
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*/
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void EllipticToRectangularN(double mu,const double elem[6],double dt,
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double xyz[]);
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void EllipticToRectangularA(double mu,const double elem[6],double dt,
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double xyz[]);
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#ifdef __cplusplus
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}
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#endif
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#endif
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