This is a web-based sexagesimal calculator for doing ancient astronomy. There is a live version available on sexagesimal.app.

It follows the notation conventions of G.J. Toomer's translation of Ptolemy's Almagest. 1.5 is written as 1;30, where 30 represents thirty parts of sixty. Likewise, 0;30,30 is equal to 0 + 30/60 + 30/(60^2). Whole numbers are in decimal notation: 12;0 = 12.0. Division is written with : instead of /, though / will be automatically converted to :.

You can also use crd to take the chord of a number. Example: 3;45*crd1;2,50. As written, this is not calculated using Ptolemy's method, though it will be eventually.

The calculator takes a query like 3;0+2;30*4;45,45 and returns a value in sexagesimal. Order of operations is PEMDAS. Decimal numbers and mixed decimal-sexagesimal expressions are also supported, e.g. 1;30*1.5. Parentheses are respected, though there may still be some instances where they do not work. An example:

Ptolemy requires Flask.

• source ptolemy-venv/bin/activate
• May need to install requirements from requirements.txt at this point.
• flask --app ptolemy run