Source: https://guthlabs.ai/docs/instruments/solar-elevation-shadow-length-calculator/implementation/

instrument implementation / implementation-contract

# Solar Elevation Shadow-Length Calculator implementation

A source-bound implementation contract for Solar Elevation Shadow-Length Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-182

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not state validation for zero elevation, elevations beyond the physical solar domain, or below-horizon sign handling. Direct arithmetic can yield Infinity at 0° and a negative or physically meaningless shadow for invalid or convention-dependent angles.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "object_height": 1.8,
    "height_unit": "m",
    "sun_elevation": 45,
    "angle_unit": "degrees"
  },
  "expected_outputs": {
    "shadow_length": 1.8,
    "unit": "m"
  },
  "working": "tan(45°) = 1. shadow = 1.8 m / 1 = 1.8 m."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/solar-elevation-shadow-length-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/solar-elevation-shadow-length-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/solar-elevation-shadow-length-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`