Suryasiddhanta 2.59

2.59

grahasya ye'yanāṃśasaṃskṛtarāśervakṣyamāṇanirakṣodayāsavastairguṇitā nijasphuṭagatiḥ kalādyāṣṭādaśaśatabhaktā phalena yutāścakrāsavaḥ ṣaṣṭighaṭikānāmasavaḥ ṣaṭśatayutaikaviṃśatisahasramitāḥ svasvagrahasyāhorātrāsavaḥ kālatattvajñaiḥ kathitāḥ | atropapattiḥ | grahaḥ pūrvagatyā lambitaḥ pravaheṇa gatibhogakālena bhacakraparivarttānantaramudetyato bhacakraparivarttakālaḥ ṣaṣṭighaṭikāmito grahagatikalāsambaddhāsvātmakakālenādhiko grahāhorātramasmātkaṃ nākṣatrapramāṇena bhavati | tatraikararāśikalābhirgrahasvasvarāśyudayaprāṇāstadā gatikalābhiḥ ka ityanupātena gatyasava ityupapannaṃ grahodayetyādi | anenaiva ślokena grahāṇāmudayāntarakarmmāstītyuktaṃ bhagavatā | tathāhi | anupātānītamadhyagrahāṇāṃ niyatāhorātramānāntarakāle siddhatvānna madhyarātrakāle grahāṇāṃ siddhiḥ | ravimadhyagatyasūnāṃ pratirāśau bhinnatvena madhyamasūyyāhorātramānasya niyatatvābhāvādatastrairāśikāvagatagrahā aniyatamadhyārkāhorātramānāntareṇārdharātre yatsaṃskāreṇa bhavanti tadevodayāntaraṃ tatsādhanaṃ bhagavatā svalpāntaratvādupekṣitam| kathamanmathā gatikalāsūnāṃ samatvamupecya gatikalānāmasavo bhagavaduktāḥ saṅgacchante | udayāntarasya gatikalāsubhedotpannatvāt |