Zmanim Calendar


This page is a demonstration of the use of the Zmanim API. It generates an annual calendar using the API. For more information on the algorithms used see the JavaDocs.

Location (1)
Latitude (2) Longitude (3) Elevation (4)
Time Zone (5) Algorithm (6) Year (7)
Calendar Type (8) Output Format Language
Time Format

1. This field will display as the location in the generated calendar. Manually entering a location will search for it (either by clicking the find button, or by changing to another field) and attempt to find it on a map. If found it will set the latitude, longitude and elevation of the first matching location found. Please ensure that the location on the map matches the location you are looking for. This look-up will not set the time zone. Please select the proper timezone.

2. Use the decimal format such as 40.096 for Lakewood, NJ. Use negative numbers south of the equator.
Note: For far northern (or southern) locations such as England some zmanim during part of the year such as early calculation of alos in the spring, that by calculation do not occur since the sun never reaches that far below the horizon (and actually calculate to an invalid mathematical value, see JavaDocs of AstronomicalCalendar for more information) will have a value of N/A. You can use the Map to select the latitude and longitude for your location. To use this feature, use the map controls to get to the desired location and click on it. This will set the longitude and latitude for the point on the map that you clicked. In addition, updating the latitude and longitude in the form will move the pin to the selected location.

3. Use the decimal format such as -74.222 for Lakewood, NJ. Use negative numbers west of the prime meridian (Greenwich). See the previous note for additional information.

4. Elevation in Meters above sea level. Negative numbers can not be used. This is used by sunrise and sunset calculations to adjust times based on elevation. Only sunrise and sunset calculations are adjusted as per Yisroel Vehazmanim and Calendrical Calcuations. When greater than 0, both sea level and elevation adjusted sunrise and sunset times will be exported. It is currently implemented by all algorithms in the Zmanim package using the formula zenith = zenith + Math.toDegrees(Math.acos(earthRadiusInMeters / (earthRadiusInMeters + elevationMeters))) found in Calendrical Calculations. A similar algorithm found in Maaglay Tzedek would be to add 0.0347 * squareRoot(elevationMeters) to the zenith. Use 0 to default to the standard algorithms.
Note: Elevation lookup courtesy of Google’s elevation API.

5. Please manually select the timezone for the selected location. Locations such as Israel where the start and end of daylight savings time varies from year to year will have an inaccurate start of daylight savings time. I will hopefully soon change the page to allow entry of optional start and end of daylight savings time.

6. Different algorithms are available for the sunrise / sunset calculations that form the basis for all zmanim calculations. USNO is the US Naval Observatory algorthm. NOAA is the National Oceanic and Atmospheric Administration algorithm.

7. The year is used to ensure correct start and end of daylight savings time. It will also ensure that the the proper Jewish date is dsplayed, that the molad times are properly calculated, and that February 29th is present on a leap year.
Note: The calculation of zmanim remain almost identical from year to year (with a drop of a change for the 1/4 day difference mostly fixed by the leap year every 4th year) using the USNO algorithm, so the calendar can be used for any year. The NOAA algorithm adjusts the calculation based on the year and will be more accurate if you set the proper year.

8. The standard calendar uses the most commonly used zmanim. Full returns an extensive set of about 130 zmanim including 13 calculations for alos etc.