Local Solar Time Calculator
Your clock keeps one standard time for a whole time zone, but the sun keeps its own. Enter your longitude, or use your location, to see local solar time, today's solar noon and the equation of time: the reference point we use when timing a birth chart or a mahurat.
About local solar time
Clock time is set for a whole time zone. All of India runs on Indian Standard Time, which is fixed to the meridian at 82.5° east, yet the sun rises in Arunachal Pradesh nearly two hours before it rises in western Gujarat. The clock says the same thing in both places; the sky does not.
Local solar time corrects for this. The sun moves across one degree of longitude every four minutes, so a place east of the zone meridian is ahead of clock time and a place west of it is behind. Delhi, at about 77° east, runs about 21 minutes behind IST.
A second correction, the equation of time, comes from the tilt of the earth and its elliptical orbit. Through the year it moves solar time up to about sixteen minutes either side of the average, which is why solar noon is not always at the same clock time.
Why it matters in astrology: the ascendant changes sign roughly every two hours, and the divisional charts change far faster. A birth time that is off by a few minutes can move the ascendant, the navamsa or the dasha dates. Enter the clock time from the birth record along with the place of birth, and the calculator gives the local solar time used to cast the chart.