FA-12171 / Astronomical coordinate conventions / Open access

Radio and optical velocity conventions use different frequency denominators · case 01

Radio and optical velocity conventions use different frequency denominators.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The observed frequency is substituted for the rest frequency regardless of the declared velocity convention.

THE FAILURE

The observed frequency is substituted for the rest frequency regardless of the declared velocity convention.

Unsuccessful approach: Using the radio formula universally reverses which convention is handled correctly.

Case contract

Positive integer frequencies f and rest; mode radio or optical. Return reduced rational v/c string: (rest-f)/rest for radio, (rest-f)/f for optical. This tests convention conversion, not a relativistic physical speed.

Why this case matters

Astronomical coordinate adapters must preserve convention semantics. Primary background: https://docs.astropy.org/en/stable/units/equivalencies.html

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(f, rest, mode):
    return str(Fraction(rest-f,f))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('radio redshift', solve(N, 2*N, "radio"), '1/2')
check('optical redshift', solve(N, 2*N, "optical"), '1')
check('radio blueshift', solve(2*N, N, "radio"), '-1')
check('optical blueshift', solve(2*N, N, "optical"), '-1/2')
check('zero shift', solve(N, N, "radio"), '0')
check('nonbinary ratio', solve(2*N, 3*N, "optical"), '1/2')
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
radio redshift	`1`	`1/2`	Failed
optical redshift	`1`	`1`	Passed
radio blueshift	`-1/2`	`-1`	Failed
optical blueshift	`-1/2`	`-1/2`	Passed
zero shift	`0`	`0`	Passed
nonbinary ratio	`1/2`	`1/2`	Passed

SHA-256 / 25e3992a6fdb50a35f72b5b43e2d0307d7da1d11b1b79c2128f7819b1ada9004

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(f, rest, mode):
    return str(Fraction(rest-f,rest))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('radio redshift', solve(N, 2*N, "radio"), '1/2')
check('optical redshift', solve(N, 2*N, "optical"), '1')
check('radio blueshift', solve(2*N, N, "radio"), '-1')
check('optical blueshift', solve(2*N, N, "optical"), '-1/2')
check('zero shift', solve(N, N, "radio"), '0')
check('nonbinary ratio', solve(2*N, 3*N, "optical"), '1/2')
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
radio redshift	`1/2`	`1/2`	Passed
optical redshift	`1/2`	`1`	Failed
radio blueshift	`-1`	`-1`	Passed
optical blueshift	`-1`	`-1/2`	Failed
zero shift	`0`	`0`	Passed
nonbinary ratio	`1/3`	`1/2`	Failed

SHA-256 / 666be9d1e665a084c05aa2cd666d05955496f7cfa0b5924fb8b7d5798726374f

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

Reduced deterministic algebraic model only; no ephemeris, full sky projection, or physical accuracy claims. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:54.376277+00:00.

Case digest / 528d84fb333622390edac68cdba173d4b7a811599cc95a7d384d839195e6c8e2