Source: https://guthlabs.ai/docs/instruments/limiting-magnitude-estimator/mechanism/

instrument mechanism / verified-clean

# Limiting Magnitude Estimator mechanism

The inspectable method record for Limiting Magnitude Estimator, kept separate from implementation and qualification.

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

## Model scope

The stated aperture-only rule can be evaluated as written, but the instrument specification is incomplete because it promises a sky conditions modifier without defining how that input affects the result. Specify the modifier's meaning and operation, for example an additive magnitude offset, before release. Retain the honest label that this is a rough rule of thumb and state the required D_mm convention and positive-domain constraint.

- The sky conditions modifier is listed as an input but no operation, sign convention, or unit is defined for applying it; the current formula ignores that input.

- The logarithm requires aperture to be a positive numerical value expressed in millimetres. The formula is a rough empirical rule, not a universal limiting-magnitude law, and its applicable observing assumptions are unspecified.

## Units and conventions

- D_mm is the clear optical aperture diameter in millimetres, not focal length, radius, or an incorrectly converted inch value.

- log10 operates on the numerical aperture value after expressing it in millimetres; physically, the logarithm should be understood as applied to D_mm divided by a 1 mm reference.

- The sky conditions modifier has no defined unit or interpretation. It cannot be included in an independently verified result until its formula is specified.

- The output is a visual stellar limiting magnitude under unspecified observer, sky, optical-transmission, magnification, and seeing assumptions.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "aperture_diameter_mm": 70,
    "sky_conditions_modifier": 0
  },
  "expected_outputs": {
    "limiting_magnitude": 11.92549
  },
  "working": "D = 70 mm. log10(70) = 1.845098. 5 × 1.845098 = 9.225490. 2.7 + 9.225490 = 11.925490. The modifier is not applied because its operation is unspecified."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The stated arithmetic formula produces undefined results for zero or negative aperture diameters, so the instrument must validate that D_mm is strictly positive. A unit-convention mismatch can also produce a large incorrect result if an aperture entered in inches is treated as millimetres.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/limiting-magnitude-estimator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/limiting-magnitude-estimator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/limiting-magnitude-estimator/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-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`