[Pramāṇa](https://indike.org/pramana/) › [Indian literature](https://indike.org/pramana/in) › [Astronomy & Mathematics](https://indike.org/pramana/in.astro) › [Mathematical Astronomy](https://indike.org/pramana/in.astro.siddhanta) › [Classical siddhāntas and the Āryabhaṭan, Brāhma and Saura schools (to c. 1200)](https://indike.org/pramana/in.astro.siddhanta.early) › Aryabhatasiddhanta (ardharatrika system) # Aryabhatasiddhanta (ardharatrika system) (Āryabhaṭasiddhānta (ārdharātrika system)) आर्यभटसिद्धान्त (आर्धरात्रिक स्य्स्तेम्) Āryabhaṭa's second work, using midnight epoch; known from fragments and from Brahmagupta's Khaṇḍakhādyaka and later reports. - **Language:** Sanskrit - **Date:** 499–550 CE - **Author:** [Āryabhaṭa](https://indike.org/pramana/person/aryabhata) - **Text:** lost ## Commentaries (4) - [Āryabhaṭasiddhāntaṭīkā](https://indike.org/pramana/in.astro.siddhanta.early.aryabhatasiddhanta!paramesvara) — Parameśvara, Sanskrit, not yet digitised - [Āryabhaṭasiddhāntaṭīkā](https://indike.org/pramana/in.astro.siddhanta.early.aryabhatasiddhanta!suryadeva) — Sūryadeva, Sanskrit, not yet digitised - [Āryabhaṭasiddhāntaṭīkā](https://indike.org/pramana/in.astro.siddhanta.early.aryabhatasiddhanta!paramadisvara) — Paramādīśvara, Sanskrit, not yet digitised - [Āryabhaṭasiddhāntaṭīkā](https://indike.org/pramana/in.astro.siddhanta.early.aryabhatasiddhanta!bhaskara) — Bhāskara, Sanskrit, not yet digitised --- Source: [https://indike.org/pramana/in.astro.siddhanta.early.aryabhatasiddhanta](https://indike.org/pramana/in.astro.siddhanta.early.aryabhatasiddhanta) · Pramāṇa