Date Verifier
Deep Time Almanac
Sun, Moon, planets and the day's panchanga at a place, from JPL DE441, for any date from 13,000 BCE to 17,000 CE.
Search Find dates that match a description up to 500 years at a time
Give a range of years and one or more conditions. The search lists every stretch of time when all the conditions hold together. It uses the ayanamsha and the Rahu and Ketu choice set above; the place and Delta T give the local date beside each result. Open loads the middle of a stretch in this page.
| # | From (TD) | To (TD) | Lasts | Middle, local | At the middle |
|---|
The moment
The day
Solstices and equinoxes
| Event | Local mean time at the place | TD | Sun: nakshatra, pada | Rasi |
|---|
Panchanga
Zodiac at the moment
Drag to move through the days around the date entered (up to 45 days either way; let go and drag again to go further) and through the hours of the day. The whole page follows.
Sidereal longitude runs anticlockwise from the start of Ashvini at the left. Outer ring: the 27 nakshatras; inner ring: the 12 rasis. WS, VE, SS and AE mark where the winter solstice, vernal equinox, summer solstice and autumnal equinox fall among the nakshatras on this date. The Moon in the centre shows its phase. The dashed line is the Rahu-Ketu axis, the line of the Moon's nodes; an R beside a planet means it is retrograde (moving backward against the stars).
Rasi grid (South Indian layout)
The same positions grouped by rasi in the traditional South Indian layout, where each sign keeps a fixed square (Mesha second from the left in the top row, the signs running clockwise). The outlined square holds the lagna, the point of the ecliptic rising in the east.
Ecliptic strip
The zodiac band drawn flat: sidereal longitude runs across, increasing to the left (east, as the sky looks), and ecliptic latitude up and down. Thin vertical lines divide the 27 nakshatras and heavier ones the 12 rasis, in the ayanamsha chosen above. No stars are drawn, only line figures: the IAU constellations (pale) and the nakshatras (gold, the yogatara ringed) with their stars as identified by E. Burgess in his translation of the Surya Siddhanta (1860), the same stars the Nakshatras page lists. Ardra, Chitra and Swati are single stars in the tradition; Shatabhisha (said to have a hundred stars) and Revati (thirty-two) show only the yogatara, as their other stars cannot be identified. Their stars are carried to this date by their own motion and by precession, so the figures stand where they stood then. Drag to move, scroll or pinch to zoom; the read-out under the strip gives the place under the pointer. The horizon line ignores refraction. Figures: d3-celestial (Olaf Frohn, BSD licence), after the IAU charts; nakshatras after Burgess, Journal of the American Oriental Society 6 (1860), notes to chapter 8. Stars: Hipparcos (van Leeuwen 2007) and SIMBAD.
Positions at the moment
| Body | Sidereal | Rasi | Nakshatra | Pada | Tropical | Per day | From Sun | Altitude |
|---|
Ayanamsha check
| System | Ayanamsha | Against chosen | Sun | Moon | Lagna |
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Eclipses near this date
| Greatest eclipse (TD) | Eclipse | Magnitude | From the moment | At the place | Seen for Delta T |
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Heliacal risings and settings
| Event | Typical sky | Clear and hazy skies | From the moment | Seen (typical sky) | Sun's depth |
|---|
Years are shown as BCE and CE, or, with the Years setting, in astronomical numbering, which has a year 0: year 0 is 1 BCE and -5649 is 5650 BCE. Links always use astronomical numbering. Dates before 15 October 1582 are usually given in the Julian calendar.
Positions are apparent geocentric longitudes from JPL DE441, carried to the equinox of date with the long-term precession of Vondrak, Capitaine and Wallace (2011). Sidereal longitude is tropical minus the chosen ayanamsha. The true node is the Moon's osculating node; the mean node smooths out its 1.5 degree wobble.
Delta T (TD minus UT) comes from the chosen model: the EclipseDB catalogue (Morrison and Stephenson 2004 parabola before 720 BCE, the Stephenson, Morrison and Hohenkerk 2016 spline after); Stephenson, Morrison and Hohenkerk 2016 with their 2020 addendum (the same spline, and before 720 BCE the integral of their long-term length-of-day function); or Espenak and Meeus 2006 (NASA). The page lists the other models' values for the date. The standard deviation follows the catalogue: 12% of Delta T before 1000 BCE, 7% to 500 CE, 3% to 1600, and from 1600 on NASA's estimate (Espenak and Meeus: about 20 s in 1600, 5 s in 1700, 1 s in 1800, 0.1 s in 1900, and after 2005 Huber's model of the Earth's random rotation changes, 31 minutes by 3000 CE). Positions do not depend on Delta T; local times, sunrise and the calendar day do.
Month names are given two ways. By the full-moon nakshatra: the month whose full moon falls in Krittika or Rohini is Karttika; Mrigashira, Ardra Margashirsha; Punarvasu, Pushya Pausha; Ashlesha, Magha Magha; the Phalgunis and Hasta Phalguna; Chitra, Svati Chaitra; Vishakha, Anuradha Vaishakha; Jyeshtha, Mula Jyeshtha; the Ashadhas Ashadha; Shravana, Dhanishtha Shravana; Shatabhisha and the Bhadrapadas Bhadrapada; Revati, Ashvini, Bharani Ashvina. The full moon's own nakshatra is always shown. By the solar rasi: an amanta month takes its name from the Sun's sidereal rasi at the new moon that begins it (Sun in Mina: Chaitra); a month with no sankranti is adhika. Purnimanta months run full moon to full moon, so in the dark fortnight they carry the next month's name.
Search lists every stretch of time, in a range of up to 500 years, when all the conditions hold together. It uses the same positions as the table: sidereal longitudes in the chosen ayanamsha, Rahu and Ketu as chosen, and the tithi from the Moon's elongation from the Sun. Each condition is followed in steps no longer than its body needs, at its greatest speed in DE441, to reach the edge of its nakshatra, rasi or range, so no stretch longer than about a minute is missed; each change is then found to the second. Times are TD, shown to the minute, and Open goes to the middle of a stretch. They do not depend on Delta T; the local date beside them does. A stretch marked "or earlier" or "or later" runs on past the range. With the mean node the first search of a span takes longer, up to half a minute, because each value of the mean node comes from fitting the Moon's orbit over about twenty years.
Lagna, the rising point of the ecliptic, is the point of the zodiac on the eastern horizon (true horizon, no refraction), in the chosen ayanamsha. It is an astronomical quantity, historically used to tell the time at night. It moves through a rasi in about two hours, so before about 1000 BCE it depends heavily on Delta T. Moonrise and moonset are for the Moon's upper limb with standard refraction, seen from the place.
Heliacal risings and settings are the first and last days a star or planet is seen near the Sun. Whether it can be seen at a moment follows Schaefer's model of the naked eye against the sky (Sky & Telescope, May 1998; Vistas in Astronomy 36, 1993): the brightness of the twilight, the dark sky and the Moon where the object stands, the dimming of its light near the horizon, and the eye's threshold, for normal eyesight at sea level. The day is the first (or last) on which it is seen at some moment between its rising and sunrise, or between sunset and its setting, going away from its conjunction with the Sun (Schaefer, Journal for the History of Astronomy 18, 1987). The skies differ in extinction, the light lost per air mass: 0.20 magnitude (clear), 0.30 (typical; Schaefer's value for ancient Memphis) and 0.40 (hazy). These are the earliest or latest days the sky allows; clouds, a raised horizon or not looking that morning make real sightings later, often by several days. For Sirius from Memphis in 139 CE the typical sky gives 20 July (Julian), the day Censorinus names for the Egyptian new year, "when the Dog Star usually rises in Egypt". Checked against the heliacal function of the Swiss Ephemeris for stars and planets between 601 BCE and 2026: most days agree exactly or within one day. Star brightness: SIMBAD; planets: astronomy-engine.
Eclipses come from the EclipseDB catalogue (JPL DE441, 13,000 BCE to 17,000 CE), read from its own data files, with its own calculation of what is seen from a place. The catalogue's Delta T is moved to this page's model and slider before that calculation, so the two pages agree for the same Delta T.
Links carry the date and place in the path and the rest in a short query, e.g. /dateverifier/21aug-5649/ayodhya?t=1200td&v=1. The date is Julian before 15 October 1582 and Gregorian from then, unless cal= says otherwise; t gives the time with its scale (td, ut or local); ay, off, node, dt and sd appear only when they differ from the defaults; v is the link version, so a cited link keeps its meaning. The bare /dateverifier/ always shows today.
Kali Yuga is counted from the civil day 18 February 3102 BCE (Julian, astronomical year -3101), a Friday, as day 0, the epoch of the siddhanta tradition. Years are Julian years of 365.25 days.
Local mean time is UT plus longitude/15 hours. Sunrise and sunset are for the Sun's upper limb with standard refraction; noon is the Sun's highest point. The panchanga limbs are those in force at local sunrise. Their end times are also given as almanacs give them, counted from that sunrise in ghati or nazhika (one sixtieth of a day, 24 minutes; nazhigai in Tamil) and pala or vinazhika (one sixtieth of a ghati, 24 seconds), the units of the Surya Siddhanta (1.11-12).