Maitrayaniya Upanishad 6.13.2

6.13.2

ghaṭitaṃ dvādaśamāsātmakatvāt dvādaśātmakaṃ vatsaraṃ saṃvatsararūpamasti, etat tasya rūpamiti sambandhaḥ| tathā coktaṃ śrībhāgavate 'yo'yaṃ kālastasya te'vyaktabandhośceṣṭāmāhuśceṣṭate yena viśvaṃ | nimeṣādirvatsarānto mahīyāṃstaṃ tveśānaṃ kṣemadhāma prapadye' iti | nimeṣādisaṃvatsarāntavyavahārāśrayaḥ kāla iti kālasvarūpamuktaṃ bhavati | idānīmuktalakṣaṇaḥ saṃvatsarākhyaḥ kālastadavayavaireva prameya iti vivakṣaṃstāvatkālākyavān sthūlatamādikrameṇa vyutpādayati, etasyetyādinā | etasya saṃvatsarātmanaḥ kālasya dvādaśa māsāḥ saṃvatsara iti śruterdvādaśamāsātmakasyārddhamuttarāyaṇaṣaṇmāsarūpamāgneyamagnidevatyamauṣṇyapradhānatvādasya ṣaṇmāsasya | arddhaṃ vāruṇaṃ varuṇadevatyaṃ dakṣiṇāyanaṣaṇmāsarūpaṃ jalapradhānatvādasya ṣaṇmāsasyetyarthaḥ | tathā ca tāpodakayoḥ kāryayoḥ paryāyeṇa niyatapravṛtyanyathānupapattyā yastaddhetubhūto'rthaḥ kalpyate sa kāla ubhayāyanānugataḥ saṃvatsarātmā siddhaityarthaḥ | idānīmayanāvayavabhūtān māsān vyutpādayiṣyaṃstadupodghātatayā nākṣatramayanadvayaṃ prakalpya taddvārā kālasadbhāvakalpanāmāha, maghādyamiti | maghānakṣatramārabhya śraviṣṭhākhyanakṣatrasyārddhamarddhāvasānaṃ yāvat savitā