Kiddush Levana
Find the moon. Plan the moment.
Hobby & exploration
One app.
A closer look.
Four mobile views of Kiddush Levana, using central London as an example location.
Explore the screens with the arrows. Select the phone screen to see it full size.
Four screens from the app
The problem
Knowing where the moon is does not establish whether someone can see it, or whether this is a suitable time for Kiddush Levana. The planner has to bring together the selected religious time window, local darkness and moon position, weather forecasts and nearby building obstructions. The selected location's time zone also matters, even when it differs from the phone's.
These factors do not carry the same priority in every situation. Waiting for clearer skies may make sense early in the window, while the final available night calls for different advice. A clear interval after midnight is also a different proposition from an accessible evening opportunity.
The solution
The implementation separates the traditional molad calculation from astronomical moon positions, then limits candidate viewing intervals to the selected start and deadline. It checks the local skyline, grades available cloud and rain forecasts, and compares usable nights with explicit rules for evening convenience and deadline urgency.
The interface explains the recommendation, points towards the moon and can identify a nearby candidate viewpoint when buildings obstruct it. Unknown forecasts and estimated building heights remain visible limitations. Offline prayer text is kept separate from the live data needed for planning; the viewing estimate is not presented as a religious ruling.
The decisions behind it
- Eligibility before preference
- The selected time window and a usable line of sight constrain the options before weather or convenience can improve their ranking.
- Conditions versus urgency
- A clearer later evening can be preferred while time remains. On the last available night, the planner also considers late windows that it would usually avoid recommending.
- Uncertainty stays visible
- Missing weather is not treated as clear sky. Building-height estimates and unmodelled obstacles limit what a recommendation can promise.
- Moon position and viewing planner
- Map, weather and location tools
- Offline prayer text