Aṣṭakavarga ('eight-source') is one of Pārāśara's most distinctive computational contributions. The idea: each of seven grahas (Sun through Saturn) is given a separate point-table, where each of eight sources (the seven grahas themselves plus the lagna) allocates one or zero bindus (points) to each of twelve signs, based on a fixed classical rule-set. The 56 sub-rules generate 12 bindus per graha-per-source; summed across the eight sources, you get the bhinnāṣṭakavarga of that graha — a 12-cell vector of point-totals indicating the favourability of each rāśi for that graha.
Summed further across all seven grahas, you get the sarvāṣṭakavarga (SAV) — a 12-cell vector of total bindus per rāśi (theoretical maximum 8 × 7 = 56 per cell; usual range 18 to 40). The SAV is one of the most-used transit-prediction inputs in classical practice. When a graha transits a sign with high SAV-bindus for that graha, the transit period tends to yield supportive effects; low bindus suggest a 'thin' transit.
The two reductions — trikoṇa-śodhana (Ch. 24) and ekādhipya-śodhana (Ch. 25) — strip out structural redundancies (triplicity overlaps and single-lordship overlaps), producing a refined piṇḍa value (Ch. 26). The piṇḍa feeds into longevity computation (piṇḍāyu) and other classical algorithms.