Āryabhaṭīya with the Commentary (with commentary) · Chapter 40

iti bhāskarasya kṛtau āryabhaṭatantrabhāṣye
gaṇitapādaḥ samāptaḥ ||
Kālakriyāpādaḥ
[ maṅgalācaraṇam ]
sūryendukhāgnimarudapkṣitidīkṣitākhyam
mūrtyaṣṭakam sakalalokahitārthabhāvam |
yaḥ abhūt svayam hi karuṇātanuḥ aprameyaḥ
tasmai namaḥ tribhuvanasthitaye śivāya ||
[ kālavibhāgaḥ kṣetravibhāgaḥ ca ]
atha gaṇitānantaram kālakriyā prastūyate | atha kaḥ kālaḥ, kā vā kriyā? atra kecit vadanti ã "kriyāvyatiriktaḥ kālaḥ" | apare ã "kriyā kālaḥ" iti | kriyāvyatiriktaḥ astu kālaḥ [kriyā vā], kim etena | asmākam tu sūryācandramasoḥ yaḥ paraḥ viprakarṣaḥ saḥ ardhamāsaḥ | yaḥ ca tayoḥ sannikarṣaḥ sa māsaḥ | evam dvādaśa māsāḥ saṃvatsaraḥ iti ādi kālaḥ | kriyā vyāpāraḥ | kālasya kriyā kālakriyā | kālaparijñānārthā kriyā iti yāvat | sā ca kriyā gatiḥ | tayā kriyayā
kālaḥ jñāyate iti etat pratipādayiṣyati | tat yathā ã
varṣam dvādaśamāsāḥ triṃśaddivasaḥ bhavet sa māsaḥ tu |
ṣaṣṭiḥ nāḍyaḥ divasaḥ ṣaṣṭiḥ ca vināḍikā nāḍī