Siddhanta school
Surya Siddhanta · सूर्य सिद्धान्त
A classical astronomical treatise defining planetary computation.
Approximate period
c. 400–1000 CE (received form)
Rights status
source_text_public_domain
What it covers
Mean and true planetary motion, time cycles, eclipse computation, and the geometry behind position calculation.
Classical siddhanta of astronomical computation: mean and true positions, ayanamsha and time reckoning.
Signature methods
- Epoch constants and mean-motion rates
- Correction procedures for true longitude
- Eclipse and shadow computation
What makes it different
Its constants shaped the Indian calendar for centuries; modern practice uses observation-based ephemerides instead, but the framework survives.
How the Siddhanta school reads a chartChapter-by-chapter summary
Surya Siddhanta is arranged in 14 chapters of mathematical astronomy. Numbering is stable across editions.
How to work through Surya Siddhanta
- 1This is a computational text, not an interpretive one — read it for how positions are produced.
- 2Chapters 1 and 2 carry the parameters and corrections everything else applies.
- 3The instrument and cosmography chapters explain the observational basis of the model.
10 entries covering the full text
These summaries describe what each chapter covers in Astravya's own words. No verses are translated or reproduced.
Glossary
- Yuga
- Long time cycle used as the computational framework.
- Manda correction
- Adjustment for a planet's unequal motion.
- Sighra correction
- Adjustment accounting for apparent motion effects.
Published rules cited from this text
No rules from this text have been published yet. Entries appear here once a reviewer releases them.
Sanskrit source text is public domain; Burgess (1860) translation is also public domain.
Every summary on these pages is Astravya's own wording of a classical principle. Sanskrit verses are not reproduced unless the source wording is out of copyright or licensed, and each published rule records its chapter, verse and rights basis.