Source: https://guthlabs.ai/docs/instruments/telescope-field-of-view/implementation/

instrument implementation / implementation-contract

# Telescope Field of View implementation

A source-bound implementation contract for Telescope Field of View; 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**: t3-017

**Effect**: Computation or source lookup only

## Input and validation requirements

- Division by zero occurs when magnification is zero.

- Zero or negative magnification is physically invalid and should be rejected; focal lengths must be positive.

- The approximation can be inaccurate for eyepieces with significant angular distortion or when the field stop limits the view.

- Very large AFOV-to-magnification results may exceed the physically usable field of the telescope or eyepiece.

## 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": {
    "eyepiece_AFOV_deg": 50,
    "magnification": 100
  },
  "expected_outputs": {
    "true_FOV_deg": 0.5,
    "true_FOV_arcmin": 30
  },
  "working": "TFOV = AFOV / M = 50 / 100 = 0.5 degrees. Arcminutes = 0.5 × 60 = 30 arcminutes."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/telescope-field-of-view/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/telescope-field-of-view/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/telescope-field-of-view/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-tranche3/tranche3-results.json`