Tithididhiti 1.31.p1.4

1.31.p1.4

vakṣyāmaḥ
dinadvaye karmakālāsparśe tadekadeśasparśe vā yugmavākyādiśāstrādyaddinagatā tithirgrāhyatvena nirṇītā tasyāṃ vihitakālāvacchinnāyāṃ sāṅgaprayogāsaṃbhavena vaiguṇyaśaṅkāyāṃ devalaḥ-yāṃ tithiṃ
samanuprāpya udayaṃ yāti bhāskaraḥ | sā tithiḥ sakalā jñeyā snānadānajapādiṣu | yāṃ tithiṃ samanuprāpya yātyastaṃ padminīpatiḥ
sā tithiḥ sakalā jñeyā snānadānādikarmasu | iti jyotiḥśāstraprasiddhatithisākalyābhāve'pi āhāryaṃ tithisākalyaṃ
vidadhadbhyāmetābhyāṃ vacanābhyāmuktaśaṅkānirāsena vihitakāle
eva tattatkarmānuṣṭhānaṃ niyamyate | prātaḥ saṃkalpayedvidvānupavāsavratādikam-iti vihitasaṃkalpakāle ca tithyantarasattve'pi
vihitatithyanusaṃdhānaṃ kāryamiti jñāpyate | kiyatparimāṇāyāstitheḥ pūrvottaratithividdhatvamuktavidhasākalyaṃ veti śaṅkāyāṃ
viṣṇudharmottare-udite daivataṃ bhānau paitryaṃ cāstamite ravau
dvimuhūrtaṃ trirahvaśca sā tithirhavyakavyayoḥ | iti | bhānorudayānantaraṃ dvimuhūrtaṃ daivataṃ tadvyāpinī tithirdaivātmake havye grāhyā,
raverastamayātpūrvamahastrimuhūrttaṃ pitryaṃ tadvyāpinī tithiḥ pitryātmake kavye grāhyetyarthaḥ | astamita iti bhūtārthāvivakṣāyā ahna
iti padena lābhāt | udaye dvimuhūrtāyā grahaṇaṃ ca trimuhūrtāyā
asaṃbhave jñeyam | trimuhūrttā na kartavyā yā tithiḥ kṣayagāminī
dvimuhūrttāpi kartavyā yā tithirvṛddhigāminī | iti dakṣavacane
śrutādapiśabdāt | dvimuhūrtaṃnyūnāyā api grāhyatvapratipādakaṃ
tu yacchāstraṃ—yathāha baudhāyanaḥ-ādityodayavelāyāṃ yā
stokāpi tithirbhavet | pūrṇā ityavagantavyā prabhūtā nodayaṃ vinā