Equinoctial ring-dial signed "A.C. Toblhanhb Mockba" (i.e. A.S. Trinidin, Moscow) undated, 18th century. One side of instrument showing inscriptions on dials (some of numerical inscriptions and the names of the signs of the Zodiac are duplicated in Arabic, using Abjad for the numerals) also the calender scale which may compensate for the equation of time.

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Equinoctial ring-dial signed "A.C. Toblhanhb Mockba" (i.e. A.S. Trinidin, Moscow) undated, 18th century. One side of instrument showing inscriptions on dials (some of numerical inscriptions and the names of the signs of the Zodiac are duplicated in Arabic, using Abjad for the numerals) also the calender scale which may compensate for the equation of time. Wellcome Collection. Source: Wellcome Collection.