SenrokaiandClaude Opus 5.5
1c86584642
bodies.json now holds, for 33 of the 38 bodies, the pole right ascension and declination and the prime meridian W of the IAU WGCCRE 2015 report (Archinal et al. 2018), with their rates and the periodic terms. They are read from NAIF's pck00011.tpc, which carries the report in a form a program can read, periodic terms and their angles included. Hyperion (chaotic), Nereid, Eris, Haumea and Makemake have no model in the report. The parser, src/app/shared/astro/rotational-elements.ts, sits beside the other source readers so the unit suite covers it. It reads data blocks only where \begindata stands alone on a line, as the kernel's own prose mentions the token mid-sentence. It reads the Fortran exponent (the Moon's -1.4D-12 d² term) and the degree-2 angles of the Mars system, where Phobos's tidal acceleration lives. NAIF numbers a small body 2 000 000 past its catalogue number, so Ceres is 2000001. Periodic terms under 0.01 degrees are left out. 0.01 degrees moves a point by 0.11 px on the largest body ever drawn (Jupiter at 641 px of radius). That drops 32 terms: - Mercury: 4 (0.0011 degrees and less) - the Moon: 8 of 13 (0.0072 and less) - Mars: 13 (0.00024 and less); its three 0.42-1.59 degree long-period terms stay - Phobos: 1 (0.0063) - Jupiter: 5 (0.0022 and less) - Europa: 1 (0.009) Kept, among others: Mimas's 44.85-degree libration, Triton's 32-degree precession, Miranda's 4.4 and Phobos's 1.14-degree libration. build.ts now checks the elements against Horizons on the real catalogue: - Every body but those five carries elements, and they do not. - The IAU day, 360 over W's rate, is within 1e-4 of Horizons' period. Measured: at most 1.8e-5 (Jupiter). Neptune gets a 0.01 ceiling: 0.89 per cent, because the report takes Karkoschka's 15.9663 h where Horizons keeps Voyager's 16.11. - The spin axis, the pole turned end for end where W runs backwards, is within 0.1 degrees of Horizons' obliquity. Measured: at most 0.058 (Venus, 177.358 against 177.3); Uranus 97.771, Pluto 119.610, Earth 23.435. Full npm run etl passes. Three mutants each fail it on the named check: - W's sign dropped: "Venus's IAU spin axis is 2.642 degrees". - Ceres looked up by catalogue number: "Body ceres has no IAU rotational elements". - W's rate read per century: "Mercury's IAU day ... 3.65e+4". Nothing is drawn from these yet. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
14 lines
632 B
TypeScript
14 lines
632 B
TypeScript
import { fetchTextCached } from './http';
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/**
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* NAIF's generic text PCK, which carries the IAU WGCCRE 2015 report's rotational elements
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* (Archinal et al. 2018, Celest Mech Dyn Astr 130:22) for every body here that has them, periodic
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* terms included, in a form a program can read rather than a table typeset in a paper. A released
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* kernel is never edited, only superseded under a new name, so the URL pins the numbers.
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*/
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const PCK_URL = 'https://naif.jpl.nasa.gov/pub/naif/generic_kernels/pck/pck00011.tpc';
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export async function fetchPckText(): Promise<string> {
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return fetchTextCached(PCK_URL, 'naif-pck00011.tpc');
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}
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