How to compare two astrology websites
Differences often come from conventions rather than simple bugs.
Different astrology websites can produce different answers from the same-looking inputs. The difference may be a defect, but it may also come from a legitimate methodology choice. The safest way to compare is to move from objective inputs and astronomical intermediates toward convention-dependent outputs.
AstroVedic360 publishes this checklist because reproducibility is more useful than asking users to trust a result blindly. If another service provides its conventions, you can often identify the exact layer where the two paths diverge.
1. Confirm the exact civil input
Write down the date, local clock time, place, latitude/longitude and IANA timezone. For historical dates, confirm whether daylight saving or a historical offset applies. During a repeated DST hour, note which occurrence is intended.
If the two services convert the local input to different UTC instants, stop there. Later planetary and Ascendant differences are expected until the instant is reconciled.
2. Compare raw planetary longitude before interpretation
Check the Sun, Moon and at least one slower planet at the same universal instant. If tropical longitudes disagree materially, the ephemeris or time conversion needs investigation. If tropical values agree but sidereal values differ, inspect ayanamsha.
Do not start with a horoscope paragraph, score or Yoga label. Those are downstream products and can hide the actual source of a mismatch.
3. Check zodiac and ayanamsha
Confirm tropical versus sidereal zodiac and the named ayanamsha. Lahiri/Chitrapaksha, Krishnamurti and other models produce different sidereal offsets. A planet or Moon close to a sign or Nakshatra boundary can therefore receive a different label.
A transparent site should show or document this convention. If it does not, exact comparison is limited.
4. Check Ascendant and house system separately
First compare the Ascendant degree. If that differs, recheck location, timezone and sidereal-time calculation. If the Ascendant agrees but house numbers differ, compare the house system.
Whole Sign houses, Placidus and other cusp systems can place the same longitude in different houses. That is a framework difference, not automatically an astronomical error.
5. For Panchang, compare the reference instant
Ask whether the displayed Tithi or Nakshatra is for midnight, current time, local sunrise or another reference instant. Then compare the transition time. A daily label without its reference instant is ambiguous.
Festival and Vrat dates add rule layers on top of the astronomical Panchanga. Regional observance rules may legitimately select different civil dates.
6. For Vargas and Dashas, inspect the rule and boundary convention
If D1 longitudes agree but a Varga differs, compare the specific divisional rule. If Vimshottari lords agree but dates drift, compare birth-balance precision and calendar date conventions.
Do not force one program to match a reference by inserting fixture-specific corrections. A methodology should generalize to other dates and locations.
7. For matching and Muhurta, expect regional rule families
Ashtakoota, Dasha Koota, Rajju, Vedha, Vasya, Manglik exceptions and Muhurta rules vary by school and region. The right comparison is rule-to-rule, not score-to-score.
When a matrix or exception has not been validated, AstroVedic360 prefers an explicit review state rather than silently guessing a universal rule.
Comparison checklist
- Same local date and clock time
- Same IANA timezone and DST occurrence
- Same latitude and longitude
- Same universal instant
- Same tropical ephemeris reference
- Same sidereal/tropical zodiac choice
- Same ayanamsha
- Same house system
- Same sunrise or reference-instant convention
- Same Varga/Dasha rule family
- Same regional festival, matching or Muhurta convention
Frequently asked questions
If two sites disagree, does that mean one is inaccurate?
Not necessarily. First determine whether they use the same instant and methodology. A disagreement under the same disclosed method is stronger evidence of an implementation issue than a difference caused by ayanamsha, house system or regional rules.
Which values should be compared first?
Start with the exact UTC instant and raw planetary longitudes. Then compare sidereal conversion, Ascendant and houses. Leave predictions, scores and festival labels until the underlying calculation path is aligned.
Why can festival dates differ even when Moon positions agree?
Festival observance can depend on Tithi at sunrise, overlap during a prescribed period, local coordinates and regional rules. The astronomical Moon can agree while the observance rule selects a different civil date.
Can AstroVedic360 guarantee it matches every traditional source?
No. The site documents its implemented conventions, publishes calculation boundaries and keeps unvalidated regional rules outside definitive conclusions.