FA-55052 / Astronomical coordinate conventions / Member archive

Echelle order coordinate: Order extraction evaluates a tilted trace on the cross-dispersion axis · case 02

The adapter reports an incorrect trace offset while other fields remain valid.

Member previewVariant 2 · 3 implementations · 6 checks per implementation

Case contract

A reduced echelle extractor uses detector x along dispersion and y across orders. The blaze coordinate is centered on bx, trace is t0+t1*x, order-normalized wavelength is k/m, and rectangular extraction bounds use half-height h about that trace. Orders m are positive. Output fields are defined by: trace_offset = d['y']-d['t0']-d['t1']*d['x']; blaze_coordinate = d['x']-d['bx']; order_wavelength = d['k']/d['m']; lower_aperture = d['t0']+d['t1']*d['x']-d['h']; upper_aperture = d['t0']+d['t1']*d['x']+d['h']; neighbor_trace = d['t0']+d['t1']*d['x']+d['pitch']

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	`{"blaze_coordinate": 3, "lower_aperture": 11, "neighbor_trace": 18, "order_wavelength": 40.0, "trace_offset": 5, "upper_aperture": 15}`	`{"blaze_coordinate": 3, "lower_aperture": 11, "neighbor_trace": 18, "order_wavelength": 40.0, "trace_offset": -5, "upper_aperture": 15}`	Failed

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