going

AR4378 is beginning to rotate out of view and displays a clear Wilson effect, that is, the apparent displacement of the umbra towards the center of the sun; once believed to be a real drop of the umbra respect to the photosphere, now is acepted to be the enhancement of back photosphere transparency due to the tangent line of view

Newt 4.5" + solar film, 1/640s ISO100

crop, b/c