Electional astrology selects the best moment to begin an undertaking based on the chart for that moment. The technique is the inverse of horary: horary asks what the chart says about a question already in motion; electional picks the moment so the chart says what you want. The classical electional checklist runs through Moon condition (waxing or waning, sign, applying aspects, void-of-course), day and hour ruler, the activity's natural significator (Venus for marriage, Mercury for contracts, Mars for surgery), and the chart's overall angularity.
How the engine evaluates moments
The two-pass algorithm. First pass: scan every day in the range and pick the best window per day at hour-level precision. This produces a heatmap, one cell per day, colored by best available score. Second pass: take the top days from pass one and rescan them at 5-minute precision to find the exact window. Up to 26,000 candidates evaluated per search, results in under 2 seconds.
Each candidate moment is scored on activity-specific weights. For a wedding, the weights favor strong Venus, applying Moon-Venus or Sun-Venus aspects, and a clear 7th house. For surgery, the weights favor a waning Moon, Mars in a stable sign, and no Moon-Mars contact within orb. For contracts, the weights penalize Mercury retrograde and reward Mercury in good aspect to Jupiter.
What the scores and grades mean
Scores run 0-100. Grade A is 90+, B is 80-89, C is 70-79, D is 60-69, F is below 60. A B-grade window is usable. An A-grade window means the chart has multiple supporting factors and no active cautions. F-grade windows are returned only when no better window exists in the range and the engine flags them with a quality advisory.
Cautions are softer than excluded ranges. A caution is a configuration the engine flagged but did not block. Example: Moon in detriment with an A-grade chart for other reasons. The chart is still good; the moon condition is the thing to weigh against the wedding tradition you are following.
Excluded ranges, and why they exist
Excluded ranges are windows the engine blocks from results because a hard stop applies. The hard stops vary by activity. Void-of-course Moon blocks every activity (universal stop). Moon out-of-bounds blocks surgery (Hellenistic medical tradition). Mercury retrograde blocks contracts and business launches (modern convention, configurable). Each excluded range is returned with the rule that triggered it, so you can override the search if your tradition disagrees with the default.
The 12 supported activities
Wedding. Surgery. Business launch. Signing contracts. Real estate purchase. Travel. Legal proceedings. Agriculture and planting. Building and construction. Investment. Creative launch. Relocation. Each has its own weight profile, drawn from the standard electional tradition (Bonatti, Lilly, Schmidt+George curation for the Hellenistic baseline).
The 12 cover the cases most working practitioners ask about. The roadmap adds first-meeting, new-job, and signing-a-lease in upcoming sprints.
When the engine returns no viable windows
Sometimes the search range is too short, the location is unfavorable for the activity, or every candidate hits a hard stop. The engine returns no_viable_windows: true with a quality advisory explaining the reason. The recommended action: widen the date range (try 60-90 days instead of 7), or relax the activity choice (a "travel" search might be better than a "business launch" if the activity is travel-for-business).
For the personal context that informs an election, the profections calculator tells you which year-lord is active. The zodiacal releasing calculator shows the L2 chapter. The transit report calculator shows what is moving through your chart in the same range. An election that lands inside an L2 peak and during a year-lord activation is the strongest configuration the technique offers.