What the graph measures
Each day, the calculator compares the apparent geocentric tropical longitude of moving Jupiter, Saturn, Uranus, Neptune, and Pluto with natal planets, the true North Node, Ascendant, and Midheaven. A contact contributes only while it is inside a one-degree orb. Its value rises in a straight line toward exactness and falls in a straight line afterward. Slow movement creates a wider run of active samples; overlapping contacts raise the combined curve.
Conjunctions and oppositions receive a peak weight of 1.25, squares 1.00, and trines and sextiles 0.75. Contacts to natal Jupiter through Pluto and the true North Node receive 60% of the ordinary target weight. These declared choices make the chart an inspectable comparison index. The number is not a percentage, risk score, or claim that an event will occur.
Use the curve with exact dates
The graph is designed to reveal long spans and clusters. It samples once per day, so the displayed closest date can differ from an exact aspect time by hours. Retrograde motion can create separate windows for the same planet, aspect, and natal point. Open the exact personal year transit timeline when minute-level crossings are the question.