Equation of Time Deviation Lookup
Qualified piecewise-linear calibration for Equation of Time Deviation Lookup. Actual independently verifieddaycoordinate/EOTsigned-minute ephemeriscalibration,calendar/longitudeconvention heldmatched. Increasingmatchedknots,noextrapolation,no universalcurve or fit. Examplesillustrative,actualsource independently verified;no safe-use approval or validated forecast.
Description
Equation-of-time values use a specified calendar coordinate and signed-minute convention.
Equation-of-time values use a specified calendar coordinate and signed-minute convention.1
This tool interpolates your independently verified ephemeris knots without calculating a new astronomical ephemeris.
When to use Equation of Time Deviation Lookup
Use this tool to estimate a response between supplied calibration knots under matched conditions.
How to use Equation of Time Deviation Lookup and how it works
- Establish a calibration matching the context, coordinate units and response units described above.
- Enter source, context, as-of date, verifiedCoordinateKnots and verifiedValueKnots; choose actualQueryCoordinate within the endpoints.
- Run the tool and read result.conditionalInterpolatedValue on the calibration response scale.
- Resolve rejected knot order, alignment or range inputs; check whether linear interpolation and the source conditions suit the intended use.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| callerVerifiedSource | Nonblank independently checked source identifier or edition; at most 1024 characters. | string | required; further conditions in the algorithm |
| callerVerifiedContext | Nonblank applicability, units and conditions; at most 1024 characters. | string | required; further conditions in the algorithm |
| callerVerifiedAsOfDate | Real Gregorian YYYY-MM-DD as-of date, years 0001–9999. The tool validates the date, not source freshness. | string | required; further conditions in the algorithm |
| verifiedCoordinateKnots | At least two finite strictly increasing coordinates from the matched calibration. | array of number | required; dense; align related rows as specified; further conditions in the algorithm |
| verifiedValueKnots | Finite response values aligned with the coordinate knots; response positivity is not generically enforced. | array of number | required; dense; align related rows as specified; further conditions in the algorithm |
| actualQueryCoordinate | Finite query within the coordinate endpoints, inclusive. | number | required; finite; further conditions in the algorithm |
Validate the supplied source, context and as-of date. Require at least two aligned finite knots with strictly increasing coordinates. Reject a query outside the closed coordinate range. Within a segment interpolate linearly between its two values; the final coordinate returns the final value directly. The helper does not fit a curve or enforce a physical response range.
y(q) = yᵢ + (yᵢ₊₁ − yᵢ) × (q − xᵢ)/(xᵢ₊₁ − xᵢ) Apply the declared units, ordering and branch conditions.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the declared output fields. | object |
| result.conditionalInterpolatedValue | Interpolated response in the caller calibration’s declared value unit. | number |
{
"input": {
"callerVerifiedSource": "independently-reviewed-calibration/edition",
"callerVerifiedContext": "Equation-of-time values use a specified calendar coordinate and signed-minute convention. This tool interpolates your independently verified ephemeris knots without calculating a new astronomical ephemeris. Synthetic reference/calibration example; replace with independently applicable evidence.",
"callerVerifiedAsOfDate": "2026-01-01",
"verifiedCoordinateKnots": [
1,
2
],
"verifiedValueKnots": [
10,
20
],
"actualQueryCoordinate": 1.5
},
"output": {
"result": {
"conditionalInterpolatedValue": 15
}
}
}Limitations and assumptions
The result is conditional on your verified calibration and its units and fixed conditions. The tool does not gather measurements, fit the underlying model, extrapolate, assess uncertainty or check calibration freshness. Positive or monotonic response values must be established where the application requires them.
Supply explicit required fields with the documented types and dense aligned arrays. Unknown fields, wrong types and nonfinite numbers are rejected. Branch-specific constraints are explained above. A successful false boolean, negative signed difference, empty slice or unresolved tie is distinct from an input error. Very large inputs or outputs may be rejected by shared resource limits.
Alternative or Complementary methods
For a related operation, use Equation of Time Extreme Dates Lookup. Equation-of-time extrema depend on the date range and astronomical convention being used.
For a related operation, use Perpetual Calendar Cycle Days Calculator. Gregorian leap rules repeat over a 400-year cycle.
References
-
Equation of Time Deviation Lookup — tool.io
Similar or alternative tools
- Equation of Time Extreme Dates Lookup
Equation-of-time extrema depend on the date range and astronomical convention being used.
- Perpetual Calendar Cycle Days Calculator
Gregorian leap rules repeat over a 400-year cycle.