Alan Leo — Original Progression Method
Alan Leo (1860–1917), the "father of modern astrology," developed the day-for-a-year progression as a systematic method for life prediction. His original approach uses raw astronomical data — the actual planetary positions computed for each day after birth — to forecast the quality of each year of life.
For the Modified Method with Vedic enhancements (4-rule system, nakshatra corrections, retrograde adjustments), see Secrets of Planetary Progressions.
How the Ephemeris is Computed
Using the Swiss Ephemeris (WASM), we compute positions for 121 data points (Day 0 = natal, Days 1–120 = years 1–120):
| Data Point | What is Computed |
|---|---|
| Planet Longitudes | Sidereal longitude (0°–360°) for Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu, Ketu, Uranus, Neptune, Pluto |
| Retrograde Status | Whether each planet is Direct (D) or Retrograde (R) on that progressed day |
| House Cusps | All 12 house cusps recalculated using Placidus system for each progressed day |
| Ascendant | The rising degree, recalculated per day |
| Midheaven (MC) | The 10th house cusp degree, recalculated per day |
| Nakshatra | Star name, pada (1–4), and nakshatra lord for each planet |
Original Method — How It Works
The Original Method uses raw progression data with no modifications. All planets progress naturally according to the ephemeris. For each year, aspects between natal and progressed positions are scored to produce a single year rating.
Step 1 — Identify Aspect Pairs
Every natal position is compared against every progressed position to find aspects:
| Natal Positions (10 points) | Progressed Positions (6 points) |
|---|---|
| Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Uranus, Ascendant, Midheaven | Sun, Mars, Venus, Mercury, Ascendant, Midheaven |
Step 2 — Detect Aspects Within Orb
Five major aspects are checked. An aspect is counted only if the angular difference falls within the orb limit:
| Aspect | Angle | Base Score | Nature |
|---|---|---|---|
| Conjunction | 0° | +4 | Variable (see below) |
| Sextile | 60° | +3 | Harmonious |
| Trine | 120° | +5 | Highly harmonious |
| Square | 90° | -4 | Challenging |
| Opposition | 180° | -5 | Strongly challenging |
Orb System — Approaching vs Separating
The system distinguishes between approaching (forming) and separating (dissolving) aspects:
| Orb Type | Default Limit | Meaning |
|---|---|---|
| Approaching | 1.5° | Aspect is forming — stronger influence, wider orb allowed |
| Separating | 1.2° | Aspect is dissolving — weaker influence, tighter orb required |
Conjunction — Benefic/Malefic Rules
Unlike other aspects, the conjunction's sign (positive or negative) depends on the planets involved:
| Planet Classification | Planets |
|---|---|
| Benefic | Sun, Venus, Moon, Jupiter, Mercury |
| Malefic | Mars, Saturn, Uranus |
| Conjunction Type | Result |
|---|---|
| Benefic + Benefic | +4 (positive) |
| Malefic + Malefic | -4 (negative) |
| Benefic + Malefic | -4 (negative) |
| Malefic + House (1 or 10) | -4 (negative) |
| Benefic + House (1 or 10) | +4 (positive) |
Step 3 — Apply Weights
Each planet and sensitive point has a weight that amplifies the aspect's influence. Higher weight = more powerful influence on life events:
| Planet / Point | Weight | Rationale |
|---|---|---|
| Midheaven (House 10) | 14 | Career, public life — highest impact |
| Ascendant (House 1) | 10 | Self, body, personality — major life axis |
| Uranus | 7 | Sudden changes, disruption |
| Saturn | 6 | Karma, discipline, restriction |
| Jupiter | 5 | Expansion, wisdom, fortune |
| Rahu | 5 | Obsession, material desire |
| Ketu | 5 | Detachment, spiritual growth |
| Sun | 4 | Soul, authority, vitality |
| Moon | 4 | Mind, emotions, mother |
| Mars | 4 | Energy, courage, conflict |
| Mercury | 2 | Communication, intellect |
| Venus | 2 | Love, beauty, comfort |
Step 4 — Calculate Weighted Score
Score = (5 + 2) × 5 = +35 points
Example 2: Progressed Mars (wt 4) square natal Saturn (wt 6)
Score = (6 + 4) × (-4) = -40 points
Example 3: Progressed Sun (wt 4) conjunction natal Midheaven (wt 14)
Score = (4 + 14) × 4 = +72 points (both benefic)
Step 5 — Retrograde Reversal
When a planet involved in the aspect has a retrograde status of R, the weighted score is reversed (sign flipped):
This means:
- A positive aspect (trine +35) becomes negative (-35) when retrograde
- A negative aspect (square -40) becomes positive (+40) — the challenge is neutralized
Three toggles control this behavior in the UI:
| Toggle | Default | Description |
|---|---|---|
| Reversal Enabled | On | Master switch for the entire retrograde reversal system |
| Natal Retrograde | On | Reverse score when the natal planet is R |
| Progressed Retrograde | On | Reverse score when the progressed planet is R |
Step 6 — Sum to Year Score
- Positive score → Favorable year (green bar in chart)
- Negative score → Challenging year (red bar in chart)
- Higher magnitude → Stronger planetary influences at play
Customizable Parameters
All parameters can be adjusted via the settings panel (gear icon) in the RVA Software tool:
| Parameter | Default | Adjustable |
|---|---|---|
| Approaching Orb | 1.5° | Yes |
| Separating Orb | 1.2° | Yes |
| Planet Weights (each) | See table above | Yes — per planet |
| Reversal Toggle | Enabled | Yes |
| Natal Retro Toggle | Enabled | Yes |
| Progressed Retro Toggle | Enabled | Yes |
| Method | Modified | Dropdown: Original / Modified |
Reading the Graph
The Alan Leo bar chart shows 120 years of life at a glance. Key features:
- Green bars = positive years (net favorable aspects)
- Red bars = negative years (net challenging aspects)
- Bar height = magnitude of the net score
- Click any bar to see the detailed aspect breakdown for that year
- Dasha sync — the graph range auto-adjusts when navigating Vimshottari Dasha periods or entering a year in the progression field
- 10Y / 20Y / All buttons — quick zoom presets