An Etymological Dictionary of Astronomy and Astrophysics

A graph on which the latitudes of → sunspots are plotted against time. It shows how sunspots migrate from high latitudes (30°- 40° north or south) to the solar equator (latitude of about 5°) during each → solar cycle, according to → Sporer’s law. The shape of these distributions, when represented for both hemispheres, resembles the wings of a butterfly. The diagram was first created by Edward W. Maunder in 1904 to illustrate the solar cycle (M.S.: SDE).

Etymology (EN): Butterfly, from M.E. butterflye, from O.E. butorfleoge, from butor, butere “butter” floge “fly,” but the etymology is not clear; → diagram.

Etymology (PE): Nemudâr, → diagram; parvânevâr “resembling a butterfly,” from parvâné “butterfly”

• -vâr similarity suffix.