Telescope Field of View mechanism

Model scope

The stated honest label appropriately identifies this as an approximation, but the user-facing name or output should say approximate true field of view unless field-stop and distortion corrections are implemented.

• AFOV/M is the standard nominal approximation, not an exact true-field formula; actual field of view depends on the eyepiece field stop and optical distortion.
• The phrase "magnification (or focal lengths)" is ambiguous because it does not explicitly identify telescope and eyepiece focal lengths or state that M = telescope focal length / eyepiece focal length.

Units and conventions

• AFOV is expressed in degrees.
• Magnification M is dimensionless and must be positive.
• If focal lengths are supplied, telescope and eyepiece focal lengths must use the same units; M = F_telescope / F_eyepiece.
• Convert degrees to arcminutes with 1 degree = 60 arcminutes.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

• 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.

Other records

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