Choose a civil year and the grahas you want to inspect. The calculator finds each interval in which the apparent geocentric longitude gap from the Sun is at or below the selected classical limit. Every boundary shows local and UTC time, the planet’s side of the Sun, its motion, and its approximate Lahiri sidereal position. Read the calculation method →
What this calendar measures
Asta is commonly used for a planet’s disappearance in the Sun’s glare; Udaya marks its return. This calculator models the interval with a simple angular rule. It compares apparent geocentric ecliptic longitudes and starts Asta when the smaller longitude gap reaches the chosen limit. The five limits are visible below, so a result can be checked without treating “combust” as an unexplained label.
Actual visibility also depends on latitude, season, atmospheric clarity, altitude above the horizon, the planet’s ecliptic latitude and brightness, and the observer’s eyesight. The table therefore describes a reproducible longitude model rather than promising the first or last visible evening. It also does not decide a ceremony date. Regional almanacs can apply observance and sunrise rules beyond this coordinate boundary.
Why the local clock can change while the event does not
The underlying planet–Sun geometry is geocentric. Changing the UTC offset only changes the displayed wall clock and which civil year contains a boundary. The calculator keeps UTC beside every local time for direct comparison. If an Asta interval begins in December and ends in January, the selected year includes the overlapping portion and marks the other boundary as outside that year.
Use Graha Vakri and Margi for motion reversals and Graha Gochara for rashi entries. Those are different events even when a Mercury or Venus Asta interval happens near a retrograde cycle.