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Different panchang sources show slightly different tithi and nakshatra end times. This is not because one is wrong — it is because they use different astronomical parameters. This page explains exactly what we use, shows our computed values, and proves our accuracy.
When you compare two panchang sources for the same date and city, you will often find tithi end times that differ by 2–5 minutes and nakshatra transitions that differ by 3–8 minutes. This is normal and expected. Here is why:
The angular correction from tropical to sidereal zodiac. Lahiri, Raman, and KP ayanamshas differ by 1–2°. Since a tithi is only 12° of Sun–Moon elongation, even 0.5° of difference shifts the transition time by several minutes.
Some sources use the centre of the solar disc crossing the horizon; others use the upper limb (first visible edge). The difference is approximately 1.3 minutes. Indian panchang tradition uses the upper limb convention, which is what we use.
Swiss Ephemeris (based on NASA JPL DE441) gives sub-arcsecond planetary positions. Meeus algorithms give the Moon to ~0.5° accuracy. Since the Moon moves ~0.5° per hour, a 0.5° error in Moon position translates to ~60 minutes of timing error. Most professional panchangs use Swiss Ephemeris or equivalent.
Panchang for Delhi vs Ujjain vs your exact coordinates — sunrise can differ by 30+ minutes depending on longitude and latitude. A panchang computed for Ujjain will show different transition times than one computed for your city. We compute for YOUR coordinates, not a reference city.
When Ekadashi spans two sunrises, different traditions pick different days for the fast. The Smarta tradition follows Arunodaya-vyapti (tithi present at pre-dawn); the Vaishnava tradition has additional rules involving Dashami contamination. This can shift the observance date by a full day.
Worked example: Makar Sankranti, 14 January 2026, Delhi (28.61°N, 77.21°E)
| Parameter | Value |
|---|---|
| Ephemeris | Swiss Ephemeris v2.10 (NASA JPL DE441) |
| Ayanamsha | Lahiri (Chitrapaksha) — ~24.22° for 2026 |
| Sunrise model | Upper limb (h₀ = −0.8333°) with 34′ atmospheric refraction |
| Moon accuracy | Sub-arcsecond (Swiss Ephemeris); ~0.5° Meeus fallback |
| Transition search | Binary search on Sun–Moon elongation, converging to 0.0001° |
These values are computed live on the server from real astronomical calculations — they are not hardcoded.
The table below shows typical variations you might see when comparing our values with other panchang sources for the same date and location.
| Element | Typical Variation | Why It Differs |
|---|---|---|
| Sunrise | ±1–2 min | Refraction model, observer elevation, upper limb vs centre disc |
| Tithi end time | ±2–5 min | Moon position accuracy, ayanamsha choice, binary search precision |
| Nakshatra end time | ±3–8 min | Moon moves ~0.5°/hr; small position error = minutes of timing error |
| Ekadashi date | ±1 day | Dwi-tithi rule interpretation (Smarta vs Vaishnava tradition) |
| Moonrise | ±5–10 min | Lunar parallax (~1°) is the largest of any visible body; topocentric correction required |
Our calculations are validated against the same primary sources that professional almanacs and observatories use — not derived from other panchang websites.
| Source | What It Covers | Accuracy |
|---|---|---|
| Swiss Ephemeris (JPL DE441) | Planetary longitudes, latitudes, speeds | Sub-arcsecond (< 0.001°) |
| USNO Solar Tables | Sunrise, sunset, twilight times | ±1–2 minutes |
| IAU Lahiri Standard | Ayanamsha (tropical → sidereal correction) | Official Indian Government standard |
| Rashtriya Panchang (CSIR) | Festival dates, tithi assignments | Exact day match |
| Surya Siddhanta / BPHS | Computation rules: tithi, nakshatra, yoga, karana, dasha | Classical definition |
| Jean Meeus, Astronomical Algorithms | Fallback planetary engine | Sun ±0.01°, Moon ±0.5° |
Same ephemeris used by professional observatories and NASA spacecraft navigation
Upper limb convention with standard atmospheric refraction (34′)
Adopted by Calendar Reform Committee (1956); ~24.22° for 2026
Official national panchang published annually by the Indian Government
Foundational texts defining how each panchang element is computed
Industry-standard reference implementation; used when Swiss Ephemeris is unavailable
Validated across 9 locations spanning 5 timezones: Delhi, Bangalore, Chennai, Ujjain (India), Bern, Vevey (Switzerland), London (UK), Singapore, Sydney (Australia)
88 automated verification tests run before every deployment. Zero tolerance for regression.
We take every discrepancy report seriously and investigate within 24 hours. If our value differs from a source you trust, we want to know — it helps us improve.
Report a DiscrepancyDeep dive into our planetary engine, panchang algorithms, dasha systems, and classical textual references.
A structured lesson on how tithi, nakshatra, yoga, and karana are computed from Sun and Moon positions.
Dekho Panchang — dekhopanchang.com