Is this chart tropical or sidereal?
Either, depending on the Tropical / Sidereal switch on the chart. The default is tropical. Sidereal mode uses the Lahiri (Chitrapaksha) ayanamsa: sidereal longitude equals tropical longitude minus that dated offset. ClockAstronomical does not offer other ayanamsa choices. When comparing with another tool, match the instant, geocentric viewpoint, and—if sidereal—the named ayanamsa.
What is a tropical planetary position?
A tropical position measures zodiac longitude from the equinox-based start of Aries for the selected date. With Tropical selected, ClockAstronomical divides that 360° circle into twelve equal 30° signs and reports the sign and degree for each displayed body. This is a coordinate convention; it is not the body's location inside an IAU constellation.
What is a sidereal planetary position?
A sidereal position measures zodiac longitude from a stellar-reference zero point instead of the equinox. With Sidereal selected, ClockAstronomical subtracts the Lahiri ayanamsa from the tropical longitude, then divides the resulting circle into twelve equal 30° signs. Other ayanamsas (for example Raman or Fagan/Bradley) can disagree with Lahiri, so always name the convention when comparing tools.
What is geocentric planetary longitude?
Geocentric planetary longitude is the body's angular position along the ecliptic as viewed from Earth's center. ClockAstronomical reports apparent longitude of date from 0° to less than 360° in the selected tropical or Lahiri sidereal zodiac. It does not report a topocentric position for your location, altitude above the horizon, ecliptic latitude, distance, or whether the body is visible.
What is the difference between a sky map and a zodiac wheel?
A local sky map normally uses an observer's place and time to show directions, the horizon, altitude, and visibility. ClockAstronomical's zodiac wheel uses no observer location: it plots one-dimensional geocentric longitudes around twelve equal signs in the selected tropical or Lahiri sidereal system. It is useful for comparing positions along the zodiac, but it cannot tell you where to look in your local sky.
Why do tropical and sidereal planetary positions differ?
They measure longitude from different reference origins. The tropical zodiac is tied to the equinox, while a sidereal zodiac applies a stellar-reference offset called an ayanamsa. Earth's axial precession slowly moves those origins apart, so the same planet can show different signs or degrees in the two systems. ClockAstronomical supports both: tropical by default, and Lahiri sidereal when you flip the chart switch. Different ayanamsas can still disagree with one another, so Lahiri is not interchangeable with every other sidereal convention.