What is sciagraphy the study of?

Sciagraphy, also spelled Sciography or Skiagraphy (Greek: σκιά "shadow" and γράφειν graphein, "write"), is a branch of science of the perspective dealing with the projection of shadows, or delineation of an object in perspective with its gradations of light and shade; for instance;

▪︎The act or art of delineating shadows correctly in drawing; the art of sketching objects with correct shading;

▪︎Sciagraphy is the use of shading and the projection of shadows to show perspective in architectural or technical drawing;

▪︎Sciagraphy in architecture is a geometrical profile or section of a building to exhibit its interior structure and also called a sciagraph.;

▪︎Sciagraphy in astronomy is the art of finding the hour of the day or night by the shadows of objects caused by the sun, moon, or stars.