Source: https://guthlabs.ai/docs/instruments/telescope-magnification/

instrument / verified-clean

# Telescope Magnification

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/telescope-magnification/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/telescope-magnification/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/telescope-magnification/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/telescope-magnification/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Earth & Space (astronomy, orbital mechanics, meteorology, geology, geodesy, oceanography)

**Tranche**: tranche-3

**Evidence ID**: t3-005

**Ledger rows**: 1

No ledger note is attached.

## Review findings

Core focal-length magnification arithmetic is valid after unit normalization, but the instrument cannot honestly provide its declared exit-pupil output without aperture and its formula. Clarify signed versus unsigned magnification, add aperture as an input, define exit pupil = aperture/M, and revise the label to state that an exit pupil larger than the observer's eye pupil may be clipped rather than categorically wasted.

### Formula and scope findings

- M = f_telescope/f_eyepiece is the standard magnitude formula for an astronomical telescope when both focal lengths use the same units and M denotes unsigned magnification. The signed angular magnification for a conventional Keplerian telescope is negative because the image is inverted.

- The spec lists exit pupil as an output but provides neither an exit-pupil formula nor the telescope aperture input required to calculate it. The standard formula is exit pupil = aperture/M = aperture × f_eyepiece/f_telescope.

- The claimed computation is ambiguous about whether magnification should be reported as a positive magnitude or as signed angular magnification.

### Unit assumptions

- Telescope and eyepiece focal lengths must be expressed in the same length units before division; mixed units require conversion.

- Focal lengths should be positive, nonzero physical focal lengths. An eyepiece focal length of zero causes division by zero.

- Exit pupil is a diameter and requires telescope aperture, expressed in a length unit compatible with the focal lengths.

- The reported magnification values below use unsigned magnification; signed Keplerian angular magnification would have the same magnitude with a negative sign.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The division-by-zero input produces an undefined magnification that must be rejected. Independently, the requested exit-pupil output cannot be computed for any vector because telescope aperture is absent from the inputs and formulas. No genuine formula-branch regime is defined.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "telescope_focal_length": 1200,
    "telescope_focal_length_unit": "mm",
    "eyepiece_focal_length": 25,
    "eyepiece_focal_length_unit": "mm"
  },
  "expected_outputs": {
    "magnification": 48,
    "exit_pupil": null
  },
  "working": "M = f_telescope / f_eyepiece = 1200 mm / 25 mm = 48. Exit pupil cannot be computed because aperture is not supplied."
}
````

## Related workflows

[Telescope Night Kitfocal lengths → M](<https://guthlabs.ai/docs/instrument-workflows/telescope-night/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche3/tranche3-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`