सूर्यरथनिर्णयः (चन्द्रस्य पक्षवृद्धिक्षयविधानम्)
पीत्वार्धमासं गच्छन्ति अमावास्यां सुरोत्तमाः पितरश्चोपतिष्ठन्ति अमावास्यां निशाकरम्
pītvārdhamāsaṃ gacchanti amāvāsyāṃ surottamāḥ pitaraścopatiṣṭhanti amāvāsyāṃ niśākaram
เมื่อ ‘ดื่ม’ ครึ่งเดือนแล้ว เหล่าเทวะผู้ประเสริฐย่อมจากไปในวันอมาวาสยา; และในวันอมาวาสยานั้นเอง ปิตฤทั้งหลายก็เข้าไปใกล้และเฝ้าปรนนิบัตินิศากร (จันทร์)
Suta Goswami (narrating the Linga Purana discourse to the sages of Naimisharanya)
It situates Amāvāsyā as a ritually potent junction where subtle beings (Devas and Pitṛs) are especially proximate, making offerings, purity, and Shiva-oriented observances (especially Pitṛ-related rites performed with Shaiva devotion) spiritually efficacious.
Indirectly, it highlights Shiva-tattva as the transcendent order (Pati) within which cosmic cycles—lunar phases, Deva movements, and Pitṛ access—operate; aligning one’s rites on Amāvāsyā supports the Pashu (soul) in loosening Pāśa (bondage) through dharmic and devotion-centered actions.
Amāvāsyā-focused Pitṛ-kārya such as tarpaṇa and śrāddha is implied; in a Shaiva frame, these are ideally performed with Shiva-smaraṇa and Linga-oriented worship to purify the practitioner and harmonize with the fortnightly (ardhamāsa) rhythm.