How joshiastro checks results against published panchangs
Verification means comparing the site's results with published panchangs for the same dates and places, and recording where they agree and differ. The site has planned this comparison but has not yet published the results.
What it is
The planned method takes a set of dates in Mumbai and other cities, matches the ayanamsa and the sunrise convention to the printed panchang, and compares each tithi, nakshatra and yoga end time. Differences are recorded with their cause.
How it is worked out or read
Until that comparison is published, the site's results should be treated as computed but not yet independently checked against printed panchangs. The method page states this.
Where it appears on this site
The status is on the method page. The software comparison article lists the settings to match.
Why verify
Any calculator, including this one, should be checked against an independent source before it is trusted. A published drik panchang for a major city is a good reference, because it is prepared carefully, states its location and is widely used. Comparing the two on several dates shows whether the calculator's methods are compatible, and builds confidence in using it for other dates and places.
Setting up a fair comparison
Use the same city as the printed almanac, the same ayanamsa, which for most drik almanacs is Lahiri, and the same date. Check which convention the almanac uses for sunrise and for the month names, amanta or purnimanta. Make sure you compare like with like: the almanac's sunrise tithi with the calculator's sunrise tithi, the almanac's nakshatra end time with the calculator's.
What to expect
With matching settings, the tithi and nakshatra at sunrise should agree on almost every day. End times usually agree within one or two minutes; differences of that size come from rounding and from small differences in sunrise definition. Sunrise and sunset times may differ by a minute or two for the same reason. If the nakshatra end times differ by an hour or more while the tithi times agree, the ayanamsa is probably different.
Choosing test dates
Include ordinary days and some harder cases: a day with a kshaya or vriddhi tithi, a day when the nakshatra changes near sunrise, a festival date and, if available, an eclipse. These are where differences in method are most likely to show. Record the results in a small table with the source, the date, and the values from each, so the comparison can be repeated later.
If the results disagree
Work through the likely causes in order: location, date and time zone; ayanamsa; sunrise convention; month system; and, for older almanacs, whether they use drik or traditional siddhanta parameters. Most disagreements resolve at one of these steps. If one remains unexplained, the Contact page on this site is the place to report it, with the details of the comparison.
Keeping a record
A comparison made once and written down can be repeated after any change to the site, which makes it a lasting check rather than a one-off test.