What this page gives you

• The window as a clock range for the city you name, with its length in minutes.
• The rule that chose it — the first one-third of the day where Shukla Pratipada runs there, Abhijit muhurta when it does not, and the daylight remainder when neither applies.
• What a named text actually prohibits, kept separate from what is followed convention. That distinction is why published times disagree with each other.
• Chitra and Vaidhriti overlaps, reported and never decisive — the digests advise avoiding them for auspicious beginnings, and they are not prohibitions.

Why the time is different in every city

Ghatasthapana is placed inside the first of three equal parts of daylight, clipped to the stretch Shukla Pratipada actually runs. Both ends of that come from local sunrise and sunset, so the window moves — in length as well as in start time — from one city to the next on the same date.

If the morning window has passed

Abhijit muhurta, the eighth of the day's fifteen muhurtas, is the time the sources sanction for a household that could not establish the kalash earlier. It is a fallback the tradition names, not a second-best invented here.

What this page does not decide

Chaitra (spring) Navratri opens a different month and is not resolved here; regional sthapana customs that place the rite outside Pratipada, and per-sampradaya sankalpa variants, are left to a family priest.