Retrograde means a planet appears to move backwards against the stars. It is also the single most exaggerated idea in popular astrology. Here is what is really happening, what tradition claims, and what it does not.
No planet ever moves backwards. Retrograde is an effect of perspective: because the Earth is moving too, a slower planet appears to drift backwards while we overtake it.
It is the same illusion as passing a car on the motorway — for a moment the other car seems to slide backwards. It isn't; your position relative to it is changing.
Technically, the planet's ecliptic longitude begins to decrease. That is exactly how Moon Compass detects it: by computing the position at two moments and checking whether longitude is rising or falling.
| Planet | Frequency | Duration | Share of the year |
|---|---|---|---|
| Mercury | 3–4 times a year | ~3 weeks | 18–20% |
| Venus | every ~18 months | ~6 weeks | 7–12% |
| Mars | every ~26 months | ~2–2.5 months | 9–22% |
The shares vary by year. Between September 2026 and September 2027, Mercury is retrograde for 67 days, Venus for 42 and Mars for 81 — while for 218 days (about 60%) none of them is retrograde at all.
That number matters. Retrograde is not the exception of the year, but it is not the rule either. Attributing everything to Mercury retrograde does not survive contact with the calendar.
Traditional astrology treats retrograde not as disaster but as progress running backwards, each planet within its own domain:
The common thread is in the prefix: re-. Revise, review, reconsider, return. Not begin.
The app treats retrograde not as a warning but as a filter, and it says plainly which planet it checks for which task:
| Task | Retrograde excluded | Why |
|---|---|---|
| Contract, application, meeting | Mercury | Documents and communication |
| Purchase | Venus + Mercury | Both value and paperwork |
| Health procedure | Mars | Intervention and surgery |
| Moving house | Mercury | Logistics and contracts dominate |
| General | — | Only the void of course Moon is checked |
Excluded days are listed on the results screen together with the reason, so "why is this day missing?" always has a visible answer.