Asthaka dialog

Give here the zero date and the duration of the year in days for the Dasa system.

Changing the zero year here is the same as changing the zero year for the Ayanamsa
but only apply to the Dasa system.
Changes are done on the fly, so you can test different values of the Ayanamsa and see
what is the effect of this change on the Dasas, Bhuktis and Antara.
Each planet has a number of years affected.

Sun: 6 years
Moon: 10 years
Mars: 7 years
Rahu: 18 years
Jupiter 16 years
Saturn: 19 years
Mercury: 17 years
Ketu: 7 years
Venus: 20 years
So Sun dasa in days is 6*(duration year)
you can choose 360 or 365.25 for the duration year.

Note: A good starting point seems Fagan and a length of 365.25 days for the year, then, perhaps, adjust the zero date accordingly of your known periods (good or bad).