Halachic day and Onah
A civil date alone is not always sufficient for a Taharah calendar The Hebrew date and the Onah - daytime or nighttime - can also be part of the calculation
Daytime and nighttime Onah
The daytime Onah is associated with the period from sunrise to sunset, while the nighttime Onah begins at sunset and continues until sunrise Events on the same civil date can therefore belong to different Onot or Hebrew dates
When does the Hebrew date change?
The Hebrew date advances with the beginning of the Halachic night rather than at civil midnight An event after sunset may therefore belong to the next Hebrew date
Why are location and time zone needed?
Sunrise and sunset depend on location TaharaSmart uses the stored location and time zone for calculation rather than assuming one clock time for every user
What if information is missing?
Your recorded events remain separate from calculated dates Calculation changes use your selected scope; input errors are shown before saving
Day begins exactly at sunrise and ends at sunset Sunset starts the night of the next Hebrew date, lasting until sunrise Civil midnight does not change the Hebrew date Future calculations preserve the source onah and resolve new boundary times for the target date, including clock changes The source day counts as day 1