Pencil

{
  "id": "MLC-T-IND-004217",
  "term": "Pencil",
  "field": "Industrial and trades",
  "definition": "A narrow, approximately cylindrical or conical beam of light rays that converges to or diverges from a single point. In geometrical optics, pencils of rays are used to trace the path of light through an optical system to analyze image formation and aberrations. A homocentric pencil is one in which all rays intersect at a single point, whereas an astigmatic pencil has two separate focal lines.",
  "subject": "Optics and imaging",
  "see_also": [
    "carpenter's pencil"
  ],
  "translations": {
    "de": "Strahlenbündel",
    "es": "haz de luz",
    "fr": "pinceau lumineux"
  },
  "url": "https://mlchart.com/terminology/industrial/pencil/"
}