FA-55198 / Astronomical coordinate conventions / Member archive

Phase center shift: A stored n-minus-one direction term is emitted as n itself · case 03

The adapter reports an incorrect line of sight direction while other fields remain valid.

Member previewVariant 3 · 3 implementations · 6 checks per implementation

Case contract

A stipulated small-field interferometer phase-center update supplies old uvw u,v,w and direction differences l,m,nminus1. Delay cycles are u*l+v*m+w*nminus1. Visibility represented by phase cycles subtracts this delay; image tangent reference and phase provenance change together. Output fields are defined by: delay_cycles = d['u']*d['l']+d['v']*d['m']+d['w']*d['dn']; shifted_phase = d['phase']-d['u']*d['l']-d['v']*d['m']-d['w']*d['dn']; reference_x = d['oldx']+d['l']; reference_y = d['oldy']+d['m']; inverse_delay = -d['u']*d['l']-d['v']*d['m']-d['w']*d['dn']; line_of_sight_direction = 1+d['dn']

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	`{"delay_cycles": 12, "inverse_delay": -12, "line_of_sight_direction": 1, "reference_x": 22, "reference_y": 29, "shifted_phase": -2}`	`{"delay_cycles": 12, "inverse_delay": -12, "line_of_sight_direction": 2, "reference_x": 22, "reference_y": 29, "shifted_phase": -2}`	Failed

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