isophote

/ˈaɪsəˌfoʊt/
noun
  1. A line on a map or diagram connecting points of equal light intensity or brightness.
    • In the photography textbook, an isophote helped illustrate how light falls across a curved surface.
    • The weather satellite image included isophotes to indicate regions with the same amount of sunlight.
    • The astronomer drew isophotes on the image of the galaxy to show areas of equal brightness.
Synonyms
What does "isophote" mean? | whatsthatwordmean | whatsthatwordmean