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Commits
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a281f22f34 |
Measure every moon and dwarf planet against Horizons from 1950 to 2100, and say on its card how far it strays
The clock reaches AD 1 to AD 3000, but only the planets' cards named a span their elements hold
over; the 25 moons and the four SBDB dwarf planets gave a source and an epoch, though
BodyRecord.orbitSource is documented as "the span they hold over". And the worst offsets the ETL
stated came from twelve New Year's Days: Nereid's year is 360 days, so all twelve fell far from
its periapsis, where a mean ellipse is furthest out. The one date the ETL checked, 2025-01-01, saw
Nereid at 2.6 degrees; it reaches 11.19.
For each moon and each SBDB dwarf planet the ETL now fetches Horizons' ICRF vectors from 1950 to
2100, every other day (daily for Nereid, at an eccentricity of 0.75, and Hyperion, whose row's
eccentricity is a quarter of its real one: every other day gave it 22.14, daily 22.23), and
measures how far the mean elements stray, at the same TDB dates. The card appends it: "JPL SBDB
osculating elements, epoch 2026 Jun 9, within 7.2 degrees of Horizons from 1950 to 2100". Worst
offsets on the real catalogue: the Moon 2.62 (2010 March 27), Phoebe 2.58 (1969, where a comment
claimed "within 2.0"), Phobos 1.26, Mimas 7.43, Iapetus 10.34, Nereid 11.19 (2039 Nov 1),
Hyperion 22.23 (2055 Feb 26), Ceres 7.12 (1953); Io 0.07, Titan 0.06, Eris 0.06.
build.ts recomputes each from the same Horizons positions and fails if an orbit other than
Standish's names no span, if a card states less than it strays, or if a body passes its ceiling:
3 degrees, and Hyperion 23, Nereid 12, Iapetus 11, Mimas 8 and Ceres 8, each explained. The
2025-01-01 check stays for reading errors, its comment no longer passing one date's offsets off as
worst ones. The Sun's note says the moons' and those four's elements were checked from 1950 to
2100, and the date field's description that each card says how far its orbit strays over that span.
In the running app Ceres's, Phobos's and Nereid's cards end "within 7.2", "1.3" and "11.2 degrees
of Horizons from 1950 to 2100".
The CLOCK_WINDOW comment also had the calendars the wrong way at AD 1: proleptic Gregorian dates
are two days behind the Julian calendar there, level from AD 200 to 300, and ten days ahead by
1582. It now says so, and names Ceres's drift where it named Phobos's, which its orbit now carries.
Controls: the ETL measuring nothing fails ("Ceres's orbit ... names no span it holds over"),
rounding the stated figure down fails on Ceres (7.1 against 7.12), and Nereid held to the general
ceiling fails at 11.19; the note and the date field without the span fail their named tests.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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cdc0cf4678 |
Read the Horizons pages the missing moons are written in, and give triaxial bodies their mean radius
The pages of the moons this branch is about to add state their size and spin in forms the ETL
did not read. Charon's gives "Radius (km, IAU2015) = 606", which none of the radius patterns
matched, so it would have come out at radius 0. Phoebe's gives "Rotational period = 9h 16.438 m",
which the hours-or-days pattern read as 9 hours flat instead of 9.274. Pluto's and the moons' GMs
are now read too ("GM (planet) km^3/s^2 = 869.326" on Pluto's page, "GM (km^3/s^2) = 106.10" on
Charon's), for placing a pair's barycentre.
Miranda and Ariel, like Phobos and Deimos already, give three semi-axes, "240x234.2x232.9". The
first figure was taken as the radius, which is the longest axis. A triaxial body now gets the
radius of the sphere of its volume, the cube root of the product, which is how the IAU states a
mean radius. That changes two bodies already shipped: Phobos 13.1 -> 11.06 km (IAU 11.08) and
Deimos 7.8 -> 6.20 km (IAU 6.2). Nothing else in bodies.json moves.
The page parsers move from tools/etl/lib/horizons.ts to src/app/shared/astro/horizons-page.ts,
as the mean-element parsers did, so the unit suite runs their tests; the ETL imports them. A
small body's command ("1;" for Ceres) is now URL-encoded: sent raw, the semicolon made Horizons
refuse the request ("one or more query parameter was not recognized").
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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48319c3fe2 |
Move the solar system on JPL's mean elements, so it stays right as the clock runs
Every body carried one set of osculating elements from Horizons at 2025-01-01, run forward by
Kepler with a GM from a table of mass ratios. That set is exact at its instant and drifts from
then on, and the clock now runs a month a second: the Moon, with Earth's mass ratio lacking its
own and the osculating axis, went round in 27.70 days instead of 27.32, 66 degrees out after a
year, and its locked face was spun at the same wrong rate.
Planets and Pluto now take Standish's Table 2a/2b ("Keplerian Elements for Approximate
Positions of the Major Planets"): elements against the J2000 ecliptic, their rates per century,
and the b, c, s, f terms of Jupiter to Pluto, fit for 3000 BC to AD 3000. Table 1 is closer near
the present (Saturn 0.23 degrees at worst 1950-2100, against 0.32 here) but is only fit for
1800-2050, and by AD 3000 has Saturn 4.3 degrees out where Table 2 holds every planet within 0.3.
The moons take JPL SSD's satellite mean elements: sidereal mean motion n to ten figures, the
periods of their node and periapsis, and each one's local Laplace plane by its pole. They
propagate with n itself, never a GM: gmForParent and its mass table are gone. Horizons still
gives size, spin and obliquity.
Both tables are read from the Internet Archive's copy of JPL's pages, pinned to one capture: the
live approx_pos page has dropped Pluto, and the live sats/elem page has dropped n and rounds the
period to four or five figures (Phobos 0.3187 d, a revolution out within a decade).
What the tables leave implicit, measured against Horizons before it was accepted:
- The precession periods are magnitudes. A node regresses on a prograde orbit and advances on a
retrograde one; a periapsis advances except where a resonance forces the eccentricity. Io's
and Europa's follow their conjunction line backwards at 2 n(Europa) - n(Io) = 0.74 degrees a
day, which is exactly the 1.625- and 1.394-year periods in the table. Read as advancing, Io
was 0.9 degrees out and Europa 2.1.
- On a retrograde orbit the node's turning is added back to the mean anomaly. Taken off, Triton
drifted a degree a year, 105 degrees by 2100.
- The Laplace frame's x axis is where the plane rises through the ICRF equator, RA of the pole
plus 90. Read against the ecliptic, Io was 2.8 degrees out, Phobos 54 and Titan 127.
Orbit lines are now drawn in their own plane and turned by a quaternion each tick, so a turning
node carries the line with the body: fixed at one date, the Moon's line would be up to 69 000 km
off it nine years on. The Earth row is the Earth-Moon barycentre, 4 700 km from Earth, 0.002
degrees from the Sun. A tidally locked moon's day is now 360 / n, its sidereal period (the Moon
27.321662 d), so it stays locked to the orbit it is drawn on.
Angular error against Horizons VECTORS (ICRF, TDB; heliocentric for planets, planet-centred for
moons), degrees, read from the live renderer's markers in the running app:
body 1950-01-01 1975-01-01 1987-07-23 2000-01-01 2025-01-01 2037-03-06 2050-01-01 2075-01-01 2100-01-01 max
mercury 0.004 0.002 0.003 0.002 0.002 0.001 0.000 0.002 0.000 0.004
venus 0.003 0.007 0.003 0.004 0.004 0.004 0.003 0.004 0.004 0.007
earth 0.003 0.008 0.002 0.005 0.004 0.009 0.003 0.002 0.003 0.009
mars 0.009 0.010 0.008 0.024 0.009 0.012 0.009 0.011 0.028 0.028
jupiter 0.063 0.030 0.171 0.135 0.013 0.020 0.056 0.041 0.075 0.171
saturn 0.080 0.064 0.018 0.320 0.066 0.114 0.044 0.164 0.177 0.320
uranus 0.018 0.169 0.068 0.050 0.101 0.015 0.141 0.017 0.114 0.169
neptune 0.070 0.028 0.004 0.021 0.036 0.037 0.013 0.029 0.072 0.072
pluto 0.045 0.054 0.041 0.033 0.019 0.020 0.023 0.027 0.026 0.054
moon 0.486 1.928 0.127 0.631 1.407 1.086 0.720 0.339 1.180 1.928
phobos 2.068 0.294 0.881 1.113 0.313 0.636 2.089 5.862 11.099 11.099
deimos 0.077 0.043 0.310 0.066 0.164 0.068 0.034 0.468 0.044 0.468
io 0.021 0.015 0.010 0.019 0.009 0.035 0.006 0.011 0.022 0.035
europa 0.036 0.039 0.053 0.064 0.078 0.032 0.006 0.034 0.044 0.078
ganymede 0.132 0.103 0.018 0.007 0.023 0.054 0.091 0.118 0.044 0.132
callisto 0.040 0.019 0.023 0.019 0.038 0.008 0.060 0.119 0.056 0.119
titan 0.003 0.019 0.023 0.023 0.027 0.028 0.048 0.008 0.014 0.048
triton 0.051 0.029 0.009 0.021 0.052 0.048 0.063 0.089 0.137 0.137
Three miss what was hoped for, and why:
- Jupiter 0.17, Saturn 0.32, Uranus 0.17 against the 0.1 hoped for: short-period perturbations
of the giants by one another, which no Keplerian fit carries. Standish states his own Table 2
errors as 600, 1 000 and 2 000 arcseconds (0.17, 0.28, 0.56 degrees). Out to AD 3000, measured
at 1800, 2200, 2400, 2600 and 3000, every planet stays within 0.3.
- The Moon, 1.9: evection (1.27) and variation (0.66), which a mean ellipse leaves out.
- Phobos, 2.1 until 2050, then 5.9 in 2075 and 11.1 in 2100, growing as the square of the time:
its tidal acceleration, which the table has no column for. Its elements are MAR080's, epoch
1950. The map's dates are also UTC where the elements are TDB, 69 s today,
which is 0.9 degrees of Phobos and nothing for anything else.
Held in place by:
- build.ts: each body's mean elements against Horizons' own osculating elements on the ETL's
2025-01-01, at most 0.25 degrees for a planet and 2.5 for a moon (measured: Uranus 0.101, the
Moon 1.407; a regressing Triton node reads 10.24 and fails), and every moon's day equal to its
sidereal period (a 1% error fails).
- Unit tests freezing nine Horizons vectors (Earth 2100, Jupiter 1950, Saturn 2075, Pluto 1975,
the Moon 2050, Io and Europa 1950, Titan and Triton 2100) through SystemOrbitsRenderer, the
Moon kept on its own turning line, the retrograde rule, the Standish terms, the Laplace frame,
and both table parsers. Nine mutants each fail the test named for them, and the two
validators each refuse a mutated build of the real catalogue.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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c38a42cbcb |
Fix what the review of this branch found, starting with the pick rule it only claimed
The off-screen rule for clicks was described in
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225d676ab0 |
Turn each body at its own rate, from Horizons' own figures
The view had one rotation in it — the planet on the detail page, at 0.08 rad/s, a number with no source. Nothing in the system view turned at all. The data was already on disk: every cached Horizons page carries how its body spins, in one of five forms. The rate in radians per second is preferred where it appears, because it is signed — that is how Venus and Uranus are known to turn backwards — then a period in hours or days, then the `9h 55m 29.711 s` the giant planets use, and finally the word every major moon here carries instead of a number: Synchronous. A tidally locked moon's day is its orbit, so Kepler supplies it from the elements already parsed and the parent it goes round. Seventeen of the eighteen bodies come out within 1% of their published period — Earth 23.934 h, Jupiter 9.925 h, Venus -5832.5 h, Io 42.5 h, Callisto 400.5 h. Titan is the exception: its page states no period at all, so it is left still rather than turned at an invented rate. The axis is the orbit normal tilted by the obliquity about the orbit's ascending node, which is where an obliquity is measured from and the only line in the orbit the elements name. The phase at the epoch is published for none of these bodies, so the face turned toward the camera is not a claim; the rate and the direction are. At true rates nothing is visible moving — Earth turns 15 degrees an hour. A clock the reader can run faster is the next piece, and the audit asks for it anyway. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016jxMkwA2rbicdGxHosecYi |
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d7e8ea1d4d |
@
Add star-map Angular app, ETL pipeline, and caveman plugin Angular 3D star map (galaxy/system/body views, Three.js rendering, navigation store) plus the NASA ETL tooling that builds the star, exoplanet and solar-system datasets, Playwright e2e suite, and the cs:caveman Claude Code plugin (command, agent, skill). Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> @ |