Samaveda Upakarma is the day Hasta stands in Sangava in Bhadrapada Shukla — Gobhila's rule for Samavedi houses. Sandhya, then samidadhanam if the fire is kept, madhyahnikam, Brahmayajnam. Then panchagavyam, the year's mahasankalpam, panchagavya prashanam, utsarjana tarpanam, a new poonal, and kankana on the wrist. If that Bhadrapada day has sankranti or an eclipse, Hasta in Sangava in Shravana is used instead. Avani Avittam is Yajur Purnima. Rigveda follows Shravana star in Shravana month. Those are different rules. Gayatri Japam is the morning after Yajurveda Upakarma, not after this day. Gobhila Grihya Sutra opens the year's study on Praushthapadi — Bhadrapada Purnima — or under Hasta. The date we show is Hasta in Sangava in Bhadrapada Shukla, not that full moon, and not Yajurveda's Shravana Purnima. Sangava is the second of the five daylight parts after sunrise. If Hasta in Sangava that Bhadrapada day carries sankranti or an eclipse, the sitting moves to Hasta in Sangava in Shravana. It often falls near Vinayaka Chaturthi; that is a different festival. Start with sandhyavandanam on the old poonal. Brahmacharis who keep the fire do samidadhanam. Then madhyahnikam. Brahmayajnam follows — Gayatri, the opening of the Vedas as the recitation has it. Householders keep sunrise sandhya and madhyahnikam, and skip the fire if they do not keep it. Then panchagavyam is made — cow dung, cow's urine, milk, curd and ghee, mixed as the prayoga says. The year's mahasankalpam — place, time, and prayaschitta for the year. After that, panchagavya prashanam, a sip of that mix. This sits between the vow and the closing of last year's study. Utsarjana tarpanam comes next, still on the old thread — water to close last year's adhyayana, not Kandarshi tarpanam and not Savitradhi. Then a new poonal with yajnopavitam paramam pavitram. The old thread goes into water. Last, kankana dharanam — a raksha thread on the wrist. Gayatri Japam on the calendar is the morning after Yajurveda Upakarma, not after this Hasta day.
