sun spot

The common opinion that the sun-spot years are the hottest is not yet fully verified.

Just before a sun-spot minimum the few spots which appear are for the most part clustered near the sun's equator.

Compare the position of the principal belts with the position of the zones of sun-spot activity in the sun.

He speaks here of a probable connection between the comet of 1843 and the great sun-spot which appeared in June 1843.

The eclipse of 1883 was at a time of rapidly decreasing solar activity, yet the Corona had the features of a Sun-spot maximum.