सूर्यरथनिर्णयः (चन्द्रस्य पक्षवृद्धिक्षयविधानम्)
ततः पञ्चदशे भागे किंचिच्छिष्टे कलात्मके अपराह्णे पितृगणा जघन्यं पर्युपासते
tataḥ pañcadaśe bhāge kiṃcicchiṣṭe kalātmake aparāhṇe pitṛgaṇā jaghanyaṃ paryupāsate
Then, when the fifteenth portion of the day—made of subtle divisions of time (kalā)—has a little remainder in the aparāhṇa (late afternoon), the hosts of the Pitṛs attend upon what is lowest and residual, awaiting offerings made at that time.
Suta Goswami
It fixes the ritual timing (aparāhṇa) when Pitṛ-related rites are effective, helping a Shaiva householder harmonize Śiva-pūjā with dharma—honoring Pitṛs while maintaining purity and order in daily worship.
Indirectly, it presents Śiva-tattva as the Lord of kāla (time): when rites are aligned with the proper divisions of time, the pashu (individual soul) reduces pasha (bondage) through disciplined observance under Pati’s cosmic order.
Ritual discipline in Pitṛ-tarpaṇa/śrāddha timing is highlighted—performing offerings in aparāhṇa, when the Pitṛs are said to be near and receptive to the rite’s subtle efficacy.