Dalton Minimum

The Dalton Minimum was a period of low sunspot count, representing low solar activity, named after the English meteorologist John Dalton, lasting from about 1790 to 1830[1] or 1796 to 1820,[2] corresponding to the period solar cycle 4 to solar cycle 7.

[3] The coronal streamers are visually confirmed in Ezra Ames and José Joaquin de Ferrer’s eclipse drawings in 1806 and indicates similarity of its magnetic field not with that of the Maunder Minimum but with that of the modern solar cycles.

[5] The cause of the lower-than-average temperatures and their possible relation to the low sunspot count are not well understood.

Recent papers have suggested that a rise in volcanism was largely responsible for the cooling trend.

One must also consider that the rise in volcanism may have been triggered by lower levels of solar output as there is a weak but statistically significant link between decreased solar output and an increase in volcanism.