FA-56140 / Astronomical coordinate conventions / Member archive

Fabry perot spectral order: Fabry-Perot dispersion changes interference order with scan channel · case 05

The adapter reports an incorrect channel dispersion while other fields remain valid.

Member previewVariant 5 · 3 implementations · 6 checks per implementation

Case contract

A reduced Fabry-Perot scan supplies optical thickness T, integer interference order m>0, cosine q of incidence angle, channel thickness step d, channel k, and separate calibration line wavelength line. Wavelength is 2*(T+k*d)*q/m. Interference order is a coordinate label, not the channel index. Output fields are defined by: wavelength = 2*(d['T']+d['k']*d['d'])*d['q']/d['m']; channel_dispersion = 2*d['d']*d['q']/d['m']; adjacent_order_wavelength = 2*d['T']*d['q']/(d['m']+1); free_spectral_interval = 2*d['T']*d['q']/d['m']-2*d['T']*d['q']/(d['m']+1); normal_incidence = 2*d['T']/d['m']; thickness_from_line = d['line']*d['m']/(2*d['q'])

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	`{"adjacent_order_wavelength": 24.8, "channel_dispersion": 1.0, "free_spectral_interval": 6.199999999999999, "normal_incidence": 62.0, "thickness_from_line": 120.0, "wavelength": 32.5}`	`{"adjacent_order_wavelength": 24.8, "channel_dispersion": 0.5, "free_spectral_interval": 6.199999999999999, "normal_incidence": 62.0, "thickness_from_line": 120.0, "wavelength": 32.5}`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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