FA-55863 / Astronomical coordinate conventions / Member archive

Astrometric perspective transport: Astrometric propagation freezes radial distance despite supplied radial velocity · case 03

The adapter reports an incorrect radial distance while other fields remain valid.

Member previewVariant 3 · 3 implementations · 6 checks per implementation

Case contract

A finite one-axis astrometric model has initial distance r>0, radial speed v, tangential speed u, elapsed t, and tangent origin x. New distance R=r+v*t remains positive for all fixtures. Direction tangent is x+u*t/R, and apparent angular rate is u*r/R**2; this is a rectilinear perspective model. Output fields are defined by: radial_distance = d['r']+d['v']*d['t']; tangential_displacement = d['u']*d['t']; direction_tangent = d['x']+d['u']*d['t']/(d['r']+d['v']*d['t']); angular_rate = d['u']*d['r']/(d['r']+d['v']*d['t'])**2; radial_fraction = d['v']*d['t']/d['r']; initial_angular_acceleration = -2*d['u']*d['v']/d['r']**2

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	`{"angular_rate": 0.09763313609467456, "direction_tangent": 5.230769230769231, "initial_angular_acceleration": -0.024793388429752067, "radial_distance": 22, "radial_fraction": 0.18181818181818182, "tangential_displacement": 6}`	`{"angular_rate": 0.09763313609467456, "direction_tangent": 5.230769230769231, "initial_angular_acceleration": -0.024793388429752067, "radial_distance": 26, "radial_fraction": 0.18181818181818182, "tangential_displacement": 6}`	Failed

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