Retrograde is a view from Earth
Most nights, a planet’s position creeps forward in ecliptic longitude against the zodiac. At certain parts of its orbit, the line of sight from Earth changes enough that the planet’s apparent longitude slows, pauses, and decreases. In Indian astrology, this backward interval is called vakri; the return to forward motion is margi, also called progressive or direct. The planet continues orbiting the Sun in its ordinary direction. The reversal belongs to the geocentric coordinate, not to the planet’s physical path through space.
Drik Panchang’s Planet Retrograde directory separates Mangal, Budha, Guru, Shukra, and Shani into dedicated year lists. Its planet pages explain four possible milestones in a retrograde zone: shadow, retrograde station, direct station, and release. Those lists print the two stations. We follow that useful editorial distinction but calculate our own dates from the bundled ephemeris. We do not reproduce Drik Panchang’s event tables or claim identical minutes.
The coordinate rule used here
The calculator asks Astronomy Engine 2.1.19 for an apparent geocentric vector and converts it to true ecliptic longitude of date. It subtracts this site’s approximate Lahiri ayanamsa to place that longitude in a sidereal 360° circle. A Vakri station is where the time derivative of that longitude changes from positive to negative; a Margi station changes from negative to positive. The rashi shown at the station is one of twelve equal 30° sectors of that sidereal circle. It is a useful positional label, not a statement about a planet’s visibility, strength, or forecast meaning.
A constant sidereal offset would leave the station instant unchanged. A real ayanamsa changes slowly over time, so the exact zero of sidereal velocity can differ slightly from the zero of tropical velocity. Our approximate Lahiri model contributes to that difference.
How a zero crossing is found
The browser estimates angular velocity with the difference between positions three hours before and three hours after a trial instant. It unwraps the 0°/360° seam so a planet crossing Mesha’s start does not appear to jump backward by almost a full circle. The supported local year is scanned in twelve-hour brackets, with one day of margin around New Year. Whenever velocity changes sign, bisection narrows the bracket to fifteen seconds. The resulting UTC instant is assigned to the requested year only if its fixed-offset local clock falls between that year’s two local midnights.
The centered six-hour velocity is a smooth numerical estimate, not an analytic derivative of a high-precision planetary ephemeris. Near a station, a different derivative span, ephemeris, reference frame, or rounding convention can change the minute. The displayed time is therefore approximate. The table intentionally omits pre-station shadow entry and post-station release, which depend on matching the station longitudes later or earlier in the loop rather than on a motion reversal.
Why Mars can have no 2026 event
A year table lists changes of direction, not every day that a planet is direct or retrograde. Drik Panchang’s Mangal page for 2027 shows a Mars retrograde cycle beginning in January 2027 and ending in April, while its 2026 list has none. If you select only Mars for 2026 here, the empty station table is a real result under this model. It does not say that Mars has no longitude or transit in that year. The Gochara calendar answers the different question of rashi entries.
Check a published list by UTC first
Drik Panchang’s 2026 Budha list shows three retrograde intervals; its Shukra list shows one. Guru and Shani also have annual station lists. Published pages can adapt their times to a detected city and daylight-saving rule. Our form asks for one fixed UTC offset across the entire year. To compare two calculators, translate each event to UTC first, then check the ephemeris, ayanamsa, coordinate definition, and whether a publisher labels a sunrise-based Panchang day or a civil date. Our table uses civil dates and prints UTC beside the local time.
The Positional Astronomy Centre’s Rashtriya Panchang explanation is a useful source for Indian sidereal and calendar terminology. This page supplies astronomical reference data and an explanation of the calculation. It does not predict personal outcomes or identify regional muhurta, festival, or observance dates.
Common questions
Does a planet stop in the sky?
Its ecliptic longitude reaches a turning point in this geocentric model. It does not become physically motionless. Other sky coordinates can still change.
Why might my date differ by one day?
The same UTC instant can fall on adjacent civil dates under different time offsets. First compare the UTC column. Then check whether the source uses daylight saving or a sunrise-based Panchang day.
Why are there several Mercury rows?
Mercury has several apparent retrograde loops in one year. Each loop has one Vakri and one Margi station, so the calendar lists both.