Print Hyperion's eccentricity as JPL measures it now, 0.105, not the archived row's 0.023

The card listed Hyperion's eccentricity under "Measured" as 0.023: the archived JPL satellite row
the orbit is drawn from gives 0.0232. JPL's current table (SAT441) gives 0.105, and Horizons'
osculating orbit ranges 0.074 to 0.132 from 1980 to 2100 (0.1099 on 2025-01-01). The row stays
the orbit: with 0.105 put into it, Hyperion is further from Horizons, not nearer (median 9.6
degrees against 7.8 over 1980-2100, as a reviewer measured), so only the card changes.

BodyRecord.measuredEccentricity carries the figure the card prints where it is not the orbit's
own; the ETL sets it for Hyperion, and buildBodyViewModel prints it. build.ts now checks every
card's eccentricity against Horizons' osculating one on 2025-01-01, within 0.03: measured at most
0.0151 (Phoebe, and the Moon, whose eccentricity swings) once Hyperion prints 0.105, where the
row put it 0.0867 out. The live Hyperion page reads "ECCENTRICITY 0.105".

Controls: the ETL with Hyperion on its row's figure fails ("Hyperion's card gives an eccentricity of
0.0232, where Horizons' osculating orbit has 0.1099"); the view model ignoring the field fails
"prints the eccentricity measured for a moon whose orbit keeps an older one".

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-09-29 19:17:06 +02:00
co-authored by Claude Opus 5.5
parent f655a4c0f7
commit 8e3a494fe9
6 changed files with 29 additions and 2 deletions
+1
View File
@@ -1512,6 +1512,7 @@
"decDeg": 83.862
},
"orbitSource": "JPL SSD satellite mean elements, epoch 2000 Jan 1",
"measuredEccentricity": 0.105,
"parentBodyId": "saturn"
},
{