FA-55342 / Astronomical coordinate conventions / Member archive

Ephemeris relative state: Topocentric target translation uses the wrong station sign · case 02

The adapter reports an incorrect topocentric position while other fields remain valid.

Member previewVariant 2 · 3 implementations · 6 checks per implementation

Case contract

A supplied ephemeris state for target T and center C is barycentric. Observer topocenter adds station displacement s and station velocity v to C. Output relative vectors use this explicit one-dimensional reduction; light-time iteration and relativity are outside scope. Output fields are defined by: geocentric_position = d['tx']-d['cx']; geocentric_velocity = d['tv']-d['cv']; observer_position = d['cx']+d['s']; observer_velocity = d['cv']+d['v']; topocentric_position = d['tx']-d['cx']-d['s']; retarded_target_position = d['tx']-d['tv']*d['dt']

Why this case matters

Catalog, detector, sky-coordinate, and spectroscopy adapters must preserve the association between numeric coordinates and their declared reference conventions.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
astronomical fixture 0	`{"geocentric_position": 71, "geocentric_velocity": 9, "observer_position": 32, "observer_velocity": 4, "retarded_target_position": 53, "topocentric_position": 73}`	`{"geocentric_position": 71, "geocentric_velocity": 9, "observer_position": 32, "observer_velocity": 4, "retarded_target_position": 53, "topocentric_position": 69}`	Failed

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