How to Use the Zmanim API
Created by KosherJava on July 3, 2005 - כ"ז סיון תשס"ה | Tagged as: Uncategorized
First add the zmanim.jar to your CLASSPATH.
Import the package and create an instance of either the AstronomicalCalendar, ZmanimCalendar or ComplexZmanimCalendar.
String locationName = "Lakewood, NJ";
double latitude = 40.0828; //Lakewood, NJ
double longitude = -74.2094; //Lakewood, NJ
TimeZone timeZone = TimeZone.getTimeZone("America/New_York");
GeoLocation location = new GeoLocation(locationName, latitude,
longitude, timeZone);
ComplexZmanimCalendar czc = new ComplexZmanimCalendar(location);
Note: The TimeZone has to be a valid timezone listed in the java.util.TimeZone.getAvailableIDs().
Note: For locations such as Israel where the beginning and end of dailight savings time can fluctuate from year to year, create a SimpleTimeZone with the known start and end of DST.
To generate zmanim, invoke:
Date sunrise = czc.getSunrise(); Date alos16 = czc.czc.getAlos16point1Degrees();
The real power of this API is the ease in calculating zmanim that are not part of the API. The mothods for doing zmanim calculations not present in the ComplexZmanimCalendar or it’s superclass the ZmanimCalendarare contained in the AstronomicalCalendar, the base class of the calendars in our API since they are generic methods for calculating time based on degrees or time before or after sunrise and sunset and are of interest for calculation beyond zmanim calculations. Here are some examples:
To get alos calculated as 14º below the horizon (as calculated in the calendars published in Montreal) use:
Date alos14 = czc.getSunriseOffsetByDegrees(14);
To get the time of mincha gedola calculated based on the MGA using a shaah zmanis based on the day starting 16.1º below the horizon (and ending 16.1º after sunset the following calculation can be used:
Date minchaGedola = czc.getTimeOffset(czc.getAlos16point1Degrees(),
czc.getShaahZmanis16Point1Degrees() * 6.5);
A slightly more complex example would be calculating plag hamincha based on a shaah zmanis that is not present in this API. While a drop more complex it is still rather easy. For example if you wanted to calculate plag based on the day starting 12º before sunrise and ending 12º after sunset as calculated in the calendars in Manchester, England (there is nothing that would prevent your calculating the day using sunrise and sunset offsets that are not identical degrees, but this would lead to chatzos being a time other than the solar transit (solar midday)). The steps involved would be to first calculate the shaah zmanis and than use that time in milliseconds to calculate 10.75 hours after sunrise starting at 12º before sunset
long shaahZmanis = czc.getSolarHour(czc.getSunriseOffsetByDegrees(12),
czc.getSunriseOffsetByDegrees(12));
Date plag = getTimeOffset(czc.getSunriseOffsetByDegrees(12),
shaahZmanis * 10.75);
on August 26, 2005 - כ"ב אב תשס"ה at 5:54 am 1.andy sinton said …
I was wondering if there’s a way to install the zmanim calculator on my Nokia 3100 (J2me equipped). i tried the .jar file but it won’t work. I’m totally naive about these things, but maybe you can help me out?
thanks
on August 26, 2005 - כ"ב אב תשס"ה at 11:50 am 2.KosherJava said …
Andy,
At this point there is no way to use this on a J2ME device. For one, J2ME does not support floating point data types (double and float) that is used in the code. There are libraries for this, but it would not work without code changes. Secondly, there is no real front end for the API. the 2 sample output classes generate PDF and Excel documents with zmanim.
on October 13, 2006 - כ"ב תשרי תשס"ז at 3:03 pm 3.Yossie Teichman said …
I was looking at the code for the zmanim API, and I found that by default, the software uses the SunTimesCalculator class for the implementation of the AstronomicalCalculator. I was wondering if you could comment on why you picked that implementation over the other two classed that are provided.
Thanks,
Yossie
on June 22, 2007 - ז' תמוז תשס"ז at 3:30 pm 4.Raphi said …
Do you have this code in .net by any chance?
on June 22, 2007 - ז' תמוז תשס"ז at 3:39 pm 5.KosherJava said …
There is no .NET implementation yet. I do have a .NET dll that uses J# that was created by AdminJew, but it is not very easy to use since it requires the use of Java within .NET. One complicating factor in porting to .NET is that .NET does not easily support switching timezones. The code should be easy to port otherwise.
on October 24, 2007 - י"ג חשון תשס"ח at 12:05 pm 6.jack boe said …
Is there a way to incorporate this by using an httprequest from an asp page. Like an xml page, where I would send the variables and get a response with the correct candle lighting time?
thanks
on October 26, 2007 - ט"ו חשון תשס"ח at 10:43 am 7.Michael Kopinsky said …
Is there a zmanim Java applet available? I would like something that I can place on my desktop as an Active Desktop item. Such things are available for candlelighting times (for example, see http://www.torahtots.com/timecapsule/cities/philadelphia.htm), but I have not found anything for zmanim, and I don’t have the applet programming skills to make it myself.
Thanks,
Michael
on October 26, 2007 - ט"ו חשון תשס"ח at 10:54 am 8.KosherJava said …
Jack,
you seem to be requesting a REST style Web Service. This is very simple using the Zmanim API, since the toString method returns an XML representation of the calendar including any zmanim that you might need. All you need is a Java Servlet that would return data from the API.
on October 26, 2007 - ט"ו חשון תשס"ח at 11:11 am 9.KosherJava said …
Michael,
At the suggestion of Dr. Irv Bromberg I started the process of modifying a visual clock that shows zmanim. It is very rough at this point, but can be seen at the alpha quality Zmanim Clock page. There are many clocks cluttering this test page, all using slightly different configurations. Clicking on the clock will bring up an actual list of zmanim. I will see if I can find time to update the code.
on October 30, 2007 - י"ט חשון תשס"ח at 3:37 pm 10.KosherJava said …
A more up to date zmanim clock is now available. It is of pre-alpha quality.