Ryan Malloy
b33d63034b
New equatorial type (24 bytes: RA/Dec/distance) captures apparent coordinates of date — what the observation pipeline computes at precession step 3 but was discarding before hour angle conversion. Matches telescope GoTo mount conventions. 24 new SQL functions (82 → 106 total): - equatorial type I/O + 3 accessors (eq_ra, eq_dec, eq_distance) - Satellite RA/Dec: eci_to_equatorial (topocentric), eci_to_equatorial_geo (geocentric) - Solar system equatorial: planet/sun/moon/small_body_equatorial - Atmospheric refraction: Bennett (1982) with domain clamp at -1 deg - Refracted pass prediction: predict_passes_refracted (horizon at -0.569 deg) - Stellar proper motion: star_observe_pm, star_equatorial_pm (Hipparcos/Gaia convention) - Light-time correction: planet/sun/small_body_observe_apparent, *_equatorial_apparent - DE equatorial variants: planet_equatorial_de, moon_equatorial_de Also includes v0.8.0 orbital_elements type (MPC parser, small_body_observe), GiST 0-based indexing fix, llms.txt updates, and doc improvements. All 18 regression suites pass. Zero build warnings (GCC + Clang).
121 lines
2.7 KiB
C
121 lines
2.7 KiB
C
/*
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* refraction_funcs.c -- Atmospheric refraction for pg_orrery
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*
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* Bennett's (1982) formula for standard atmosphere, with optional
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* pressure/temperature correction per Meeus (1991).
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*
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* Domain guard: clamp geometric elevation to -1 deg before tan()
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* evaluation. Below that, Bennett's formula is outside its valid
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* range and we return 0.
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*/
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#include "postgres.h"
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#include "fmgr.h"
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#include "types.h"
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#include <math.h>
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PG_FUNCTION_INFO_V1(atmospheric_refraction);
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PG_FUNCTION_INFO_V1(atmospheric_refraction_ext);
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PG_FUNCTION_INFO_V1(topo_elevation_apparent);
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#define RAD_TO_DEG (180.0 / M_PI)
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#define DEG_TO_RAD (M_PI / 180.0)
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/*
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* bennett_refraction -- core Bennett (1982) formula
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*
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* Input: geometric elevation in degrees
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* Output: refraction correction in degrees (>= 0)
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*
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* R = 1/tan(h + 7.31/(h + 4.4)) arcminutes
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* where h is the geometric elevation in degrees.
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*
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* The formula diverges near h = -4.4 deg; clamp to -1 deg
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* (below which the atmosphere model is meaningless anyway).
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*/
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static double
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bennett_refraction(double h_deg)
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{
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double h, R;
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if (h_deg < -1.0)
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return 0.0;
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h = fmax(h_deg, -1.0);
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/* Bennett's formula: arcminutes */
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R = 1.0 / tan((h + 7.31 / (h + 4.4)) * DEG_TO_RAD);
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if (!isfinite(R))
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return 0.0;
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/* Convert arcminutes to degrees */
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R /= 60.0;
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if (R < 0.0)
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R = 0.0;
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return R;
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}
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/*
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* atmospheric_refraction(elevation_deg) -> refraction_deg
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*
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* Standard atmosphere: P = 1010 mbar, T = 10 C.
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*/
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Datum
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atmospheric_refraction(PG_FUNCTION_ARGS)
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{
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double h_deg = PG_GETARG_FLOAT8(0);
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PG_RETURN_FLOAT8(bennett_refraction(h_deg));
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}
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/*
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* atmospheric_refraction_ext(elevation_deg, pressure_mbar, temp_celsius)
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* -> refraction_deg
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*
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* Meeus correction for non-standard atmosphere:
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* R_corrected = R * (P / 1010.0) * (283.0 / (273.0 + T))
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*/
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Datum
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atmospheric_refraction_ext(PG_FUNCTION_ARGS)
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{
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double h_deg = PG_GETARG_FLOAT8(0);
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double P = PG_GETARG_FLOAT8(1);
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double T = PG_GETARG_FLOAT8(2);
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double R;
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R = bennett_refraction(h_deg);
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/* Meeus pressure/temperature correction */
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R *= (P / 1010.0) * (283.0 / (273.0 + T));
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if (!isfinite(R) || R < 0.0)
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R = 0.0;
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PG_RETURN_FLOAT8(R);
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}
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/*
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* topo_elevation_apparent(topocentric) -> apparent_elevation_deg
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*
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* Geometric elevation from the topocentric type plus Bennett's
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* atmospheric refraction correction.
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*/
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Datum
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topo_elevation_apparent(PG_FUNCTION_ARGS)
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{
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pg_topocentric *topo = (pg_topocentric *) PG_GETARG_POINTER(0);
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double el_deg;
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double refr;
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el_deg = topo->elevation * RAD_TO_DEG;
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refr = bennett_refraction(el_deg);
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PG_RETURN_FLOAT8(el_deg + refr);
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}
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