FAQ: Different Parshas Hashavua in Eretz Yisrael Than Chutz La’aretz

Zmanim API FAQ


Why does the KosherJava Zmanim API seem to sometimes return the incorrect parshas hashavua in Israel?


I have had a number of inquiries this year about the incorrect Parshas Hashavua being returned by the API. In all cases this has been a complaint for Eretz Yisrael and not Chutz La’aretz. The explanation is pretty simple and covered in the API documentation for the JewishCalendar class, but may not be clear to all. When the first day of Pesach occurs on a Shabbos, as it did this year (5775), the last day of Pesach in Eretz Yisrael is on a Friday. The following day is a regular Shabbos in Eretz Yisrael with the usual krias hatorah, but in chutz la’aretz it is the 8th day of Pesach, resulting in Pesach kriah. The following weeks will have different krias hatorah in Eretz Yisrael vs chutz la’aretz, and this will continue for a number of weeks until a double parsha in chutz laaretz is added to equalize the parsha. This last occurred in 2012 (before the release of the calendar functionality in the Zmanim 1.3 release), and will occur again next year. If you are coding to display the Parshas Hashavuah for use in Israel, it is important to set the inIsrael flag (it defaults to false).


A fuller example showing how to set the indicator and showing the comparison of Eretz Yisrael and Chutz Laaretz this year can be seen in this example.

JewishCalendar israelCalendar = new JewishCalendar(5775, JewishDate.NISSAN, 7);
israelCalendar.setInIsrael(true); //set the calendar to Israel
JewishCalendar chutsLaaretzCalendar = new JewishCalendar(5775, JewishDate.NISSAN, 7);
chutsLaaretzCalendar.setInIsrael(false); //not really needed since the API defaults to false
HebrewDateFormatter hdf = new HebrewDateFormatter();
System.out.println("Date\tChutz Laaretz / Eretz Yisrael"));
for(int i = 0; i < 57; i++){
	israelCalendar.forward(); //roll the date forward a day
	chutsLaaretzCalendar.forward(); //roll the date forward a day
	if(chutsLaaretzCalendar.getDayOfWeek() == 7){ //ignore weekdays
		System.out.println(hdf.formatParsha(chutsLaaretzCalendar) + "\t" + hdf.formatParsha(israelCalendar) + " \\ " + hdf.format(chutsLaaretzCalendar));

the output of this is

Date               Chutz Laaretz / Eretz Yisrael
8 Nissan, 5775     Tzav / Tzav
15 Nissan, 5775     / 
22 Nissan, 5775     / Shmini
29 Nissan, 5775    Shmini / Tazria Metzora
6 Iyar, 5775       Tazria Metzora / Achrei Mos Kedoshim
13 Iyar, 5775      Achrei Mos Kedoshim / Emor
20 Iyar, 5775      Emor / Behar
27 Iyar, 5775      Behar Bechukosai / Bechukosai
5 Sivan, 5775      Bamidbar / Bamidbar

It should be noted that this discrepancy is not rare and happens about 25% of the calendar years.

FAQ: Calculating the Baal Hatanya’s Shkiah

Zmanim API FAQ


How do I calculate the Baal Hatanya’s Zman for Shkiah as 4 minutes after sunset using the KosherJava Zmanim API?


I was recently asked how to use the Zmanim API to calculate the Baal Hatanya’s opinion is that shkiah (halachic sunset) is 4 minutes after civil sunset. The assumption that the Baal Hatanya’s shkiah is a fixed 4 minutes after sunset is not that simple and will require a separate post to clarify. This zman should not be used lehalacha without consulting a rov. This post shows how to us the API assuming that it is a fixed 4 minutes after sunset. The technique to calculate this with the API is identical to the way getTzais72() would be calculated. The source of that method is

public Date getTzais72() {
    return getTimeOffset(getSeaLevelSunset(), 72 * MINUTE_MILLIS);

The getTimeOffset(Date time, double offset) method in the base class AstronomicalCalendar is very simple:

public Date getTimeOffset(Date time, long offset) {
    if (time == null || offset == Long.MIN_VALUE) {
        return null;
    return new Date(time.getTime() + offset);

The getTimeOffset method simply adds the number of milliseconds of the offset to the raw time of the zman and returns it as a date. While using the API itself is not needed for such a simple calculation, here is how it would be used:

String locationName = "Jerusalem";
double latitude = 31.778; // Har habayis
double longitude = 35.2354;// Har Habayis
double elevation = 0;
TimeZone timeZone = TimeZone.getTimeZone("Asia/Jerusalem");
GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
ZmanimCalendar zc = new ZmanimCalendar(location);
Date baalHatanyaShkiah = zc.getTimeOffset(zc.getSeaLevelSunset(), 4 * 60000);
System.out.println("Baal Hatanya Shkiah: " + baalHatanyaShkiah);

Adding it to the API itself would be even simpler:

public Date getShkiahBaalHatanya() {
    return getTimeOffset(getSeaLevelSunset(), 4 * MINUTE_MILLIS);

At some point in the future I may (doubtful) add this time to the API itself. The zman is not commonly used, and the Chabad calendars that I have seen all use regular sunset.

Update on ‍‍July 5, 2015 – י״ח תמוז תשע״ה: This article was updated to clarify that the Baal Hatanya’s opinion may not be a fixed 4 minutes, but that the post was showing how to use the API to calculate it based on the questioner’s assumption that it was a 4 minute zman.

Using the Zmanim API 1.3.0 Jewish Calendar Code

Java CalendarThe recently released Zmanim API 1.3.0 added Jewish calendar support to the API. Previously, the API had zmanim support, but no Jewish calendar support. While the calendar code is in beta mode and is subject to API changes, below are some simple code examples using the current 1.3.0 release. These examples of the use of the JewishCalendar and HebrewDateFormatter classes do not fully cover the functionality available in the Zmanim API. Please read the JavaDocs and experiment. Please let me know if there are any calendar related items that you feel should change or be added to the API.

Setting and outputting formatted dates

JewishCalendar jd = new JewishCalendar(); // current date 23 Nissan, 5773
HebrewDateFormatter hdf = new HebrewDateFormatter();
System.out.println(jd); // prints hebrew date in English chars - 23 Nissan, 5773
hdf.setHebrewFormat(true); // change formatting to Hebrew
System.out.println(hdf.format(jd)); // date formatted in Hebrew
jd.setJewishDate(5729, JewishDate.SHEVAT, 21); // set the date to 21 Shevat, 5729
System.out.println(hdf.format(jd)); // date formatted in Hebrew
jd.setJewishDate(5772, JewishDate.NISSAN, 18); // set date to third day of Pesach
System.out.println(hdf.formatYomTov(jd)); //output Chol Hamoed Pesach in Hebrew
hdf.setHebrewFormat(false); // change formatting to default
System.out.println(hdf.format(jd)); // prints Hebrew date in English chars - 18 Nissan, 5772
System.out.println(hdf.formatYomTov(jd)); //output Chol Hamoed Pesach


23 Nissan, 5773
כ״ג ניסן תשע״ג
כ״א שבט תשכ״ט
י״ח ניסן תשע״ב
חול המועד פסח
18 Nissan, 5772
Chol Hamoed Pesach

Parshas Hashavua

Please note that the parsha will only input if the date is a Shabbos. This is something that may change down the line.

HebrewDateFormatter hdf = new HebrewDateFormatter();
JewishCalendar jd = new JewishCalendar(5773, JewishDate.NISSAN, 12);
System.out.println("Parsha on Friday [" + hdf.formatParsha(jd) + "]"); //no Parsha output on a non Shabbos
jd.setJewishDate(5773, JewishDate.TAMMUZ, 28); //double parsha


Parsha on Friday []
מטות מסעי

Rosh Chodesh

HebrewDateFormatter hdf = new HebrewDateFormatter();
JewishCalendar jd = new JewishCalendar(5773, JewishDate.NISSAN, 1);
if(jd.isRoshChodesh()){ //not necessary for formatter
jd.forward();// roll calendar to second day of Nisan
System.out.println("output[" + hdf.formatRoshChodesh(jd) + "]"); //no output for Rosh Chodesh Formatting


Rosh Chodesh Nissan
ראש חודש ניסן

Daf Yomi

JewishCalendar jd = new JewishCalendar();
HebrewDateFormatter hdf = new HebrewDateFormatter();
System.out.println(hdf.format(jd)); //output current formatted date "13 Nissan, 5773"
Daf daf = jd.getDafYomiBavli(); //get the current daf
System.out.println(daf.getMasechtaTransliterated()); //outout transliterated masechta name "Eruvin"
System.out.println(daf.getDaf()); //output current daf (page) number "16"
System.out.println(hdf.formatDafYomiBavli(daf)); //outout the formatted date "Eruvin 16"
hdf.setHebrewFormat(true); //set formatted to Hebrew
System.out.println(hdf.format(jd)); //output date in Hebrew "י״ג ניסן תשע״ג"
System.out.println(daf.getMasechta()); // output masechta name in Hebrew "עירובין"
System.out.println(hdf.formatHebrewNumber(daf.getDaf()));//output the daf number formatted in Hebrew "ט״ז"
System.out.println(hdf.formatDafYomiBavli(daf)); //output daf and masechta in Hebrew "עירובין ט״ז"


13 Nissan, 5773
Eruvin 16
י״ג ניסן תשע״ג
עירובין ט״ז


JewishCalendar jd = new JewishCalendar(5772, JewishDate.KISLEV, 25); //set date to first day of Chanukah
HebrewDateFormatter hdf = new HebrewDateFormatter();
System.out.println(jd);//output current transliterated date
System.out.println(jd.getDayOfChanukah()); //output #1
System.out.println(hdf.formatYomTov(jd)); //output Chanukah 1
hdf.setHebrewFormat(true); //set format to hebrew
System.out.println(hdf.formatHebrewNumber(jd.getDayOfChanukah())); //output 1 in Hebrew
System.out.println(hdf.formatYomTov(jd)); // output Chanukah 1 in hebrew


25 Kislev, 5772
Chanukah 1
א׳ חנוכה

Note, that there is no simple way at this point to output just Chanukah. This will likely change in the future to match Chanukah to the behavior of other Yomim Tovim.

Loop and output an entire year

JewishCalendar jc = new JewishCalendar(5773, JewishDate.TISHREI, 1);
jc.setInIsrael(false); //default false for clarity but not needed. Set to true for Israel
HebrewDateFormatter hdf = new HebrewDateFormatter();
HebrewDateFormatter hdfTransliterated = new HebrewDateFormatter();
String hebrewOutput = "";
String transliteratedOutput = "";
while(jc.getJewishYear() == 5773){
	hebrewOutput = hdf.format(jc);
	transliteratedOutput = hdfTransliterated.format(jc);
	if (jc.isYomTov() || jc.isTaanis()) {
		hebrewOutput += ", " + hdf.formatYomTov(jc);
		transliteratedOutput += ", " + hdfTransliterated.formatYomTov(jc);
	} else if(jc.getDayOfWeek() == 7){
		hebrewOutput += " - " + hdf.formatParsha(jc);
		transliteratedOutput += " - " + hdfTransliterated.formatParsha(jc);
	if (jc.isChanukah()) {
		if (hebrewOutput.length() > 0) {
			hebrewOutput += ", ";
			transliteratedOutput += ", ";
		hebrewOutput += hdf.formatYomTov(jc);
		transliteratedOutput  += hdfTransliterated.formatYomTov(jc);
	if (jc.isRoshChodesh()) {
		if (hebrewOutput.length() > 0) {
			hebrewOutput += ", ";
			transliteratedOutput += ", ";
		hebrewOutput += hdf.formatRoshChodesh(jc);
		transliteratedOutput += hdfTransliterated.formatRoshChodesh(jc);
	if(jc.getDayOfOmer() > 0){
		hebrewOutput += ", ";
		transliteratedOutput += ", ";
		hebrewOutput += hdf.formatOmer(jc);
	System.out.println(transliteratedOutput + " - " + hebrewOutput);

Output (most days removed for brevity):

1 Tishrei, 5773, Rosh Hashana - א׳ תשרי תשע״ג, ראש השנה
2 Tishrei, 5773, Rosh Hashana - ב׳ תשרי תשע״ג, ראש השנה
3 Tishrei, 5773, Fast of Gedalyah - ג׳ תשרי תשע״ג, צום גדליה
4 Tishrei, 5773 - ד׳ תשרי תשע״ג
6 Tishrei, 5773 - Vayeilech - ו׳ תשרי תשע״ג - וילך
10 Tishrei, 5773, Yom Kippur - י׳ תשרי תשע״ג, יום כיפור
15 Tishrei, 5773, Succos - ט״ו תשרי תשע״ג, סוכות
16 Tishrei, 5773, Succos - ט״ז תשרי תשע״ג, סוכות
17 Tishrei, 5773, Chol Hamoed Succos - י״ז תשרי תשע״ג, חול המועד סוכות
18 Tishrei, 5773, Chol Hamoed Succos - י״ח תשרי תשע״ג, חול המועד סוכות
19 Tishrei, 5773, Chol Hamoed Succos - י״ט תשרי תשע״ג, חול המועד סוכות
20 Tishrei, 5773, Chol Hamoed Succos - כ׳ תשרי תשע״ג, חול המועד סוכות
21 Tishrei, 5773, Hoshana Rabbah - כ״א תשרי תשע״ג, הושענא רבה
22 Tishrei, 5773, Shemini Atzeres - כ״ב תשרי תשע״ג, שמיני עצרת
23 Tishrei, 5773, Simchas Torah - כ״ג תשרי תשע״ג, שמחת תורה
30 Tishrei, 5773, Rosh Chodesh Cheshvan - ל׳ תשרי תשע״ג, ראש חודש חשוון
1 Cheshvan, 5773, Rosh Chodesh Cheshvan - א׳ חשוון תשע״ג, ראש חודש חשוון
25 Kislev, 5773, Chanukah 1 - כ״ה כסלו תשע״ג, א׳ חנוכה
26 Kislev, 5773, Chanukah 2 - כ״ו כסלו תשע״ג, ב׳ חנוכה
27 Kislev, 5773, Chanukah 3 - כ״ז כסלו תשע״ג, ג׳ חנוכה
28 Kislev, 5773, Chanukah 4 - כ״ח כסלו תשע״ג, ד׳ חנוכה
29 Kislev, 5773, Chanukah 5 - כ״ט כסלו תשע״ג, ה׳ חנוכה
1 Teves, 5773, Chanukah 6, Rosh Chodesh Teves - א׳ טבת תשע״ג, ו׳ חנוכה, ראש חודש טבת
2 Teves, 5773 - Miketz, Chanukah 7 - ב׳ טבת תשע״ג - מקץ, ז׳ חנוכה
3 Teves, 5773, Chanukah 8 - ג׳ טבת תשע״ג, ח׳ חנוכה
10 Teves, 5773, Tenth of Teves - י׳ טבת תשע״ג, עשרה בטבת
15 Shevat, 5773, Tu B'Shvat - ט״ו שבט תשע״ג, ט״ו בשבט
21 Shevat, 5773 - כ״א שבט תשע״ג
11 Adar, 5773, Fast of Esther - י״א אדר תשע״ג, תענית אסתר
14 Adar, 5773, Purim - י״ד אדר תשע״ג, פורים
15 Adar, 5773, Shushan Purim - ט״ו אדר תשע״ג, פורים שושן
27 Adar, 5773 - Vayakhel Pekudei - כ״ז אדר תשע״ג - ויקהל פקודי
15 Nissan, 5773, Pesach - ט״ו ניסן תשע״ג, פסח
16 Nissan, 5773, Pesach,  - ט״ז ניסן תשע״ג, פסח, א׳ בעומר
17 Nissan, 5773, Chol Hamoed Pesach,  - י״ז ניסן תשע״ג, חול המועד פסח, ב׳ בעומר
18 Nissan, 5773, Chol Hamoed Pesach,  - י״ח ניסן תשע״ג, חול המועד פסח, ג׳ בעומר
19 Nissan, 5773, Chol Hamoed Pesach,  - י״ט ניסן תשע״ג, חול המועד פסח, ד׳ בעומר
20 Nissan, 5773, Chol Hamoed Pesach,  - כ׳ ניסן תשע״ג, חול המועד פסח, ה׳ בעומר
21 Nissan, 5773, Pesach,  - כ״א ניסן תשע״ג, פסח, ו׳ בעומר
22 Nissan, 5773, Pesach,  - כ״ב ניסן תשע״ג, פסח, ז׳ בעומר
23 Nissan, 5773,  - כ״ג ניסן תשע״ג, ח׳ בעומר
26 Nissan, 5773 - Shmini,  - כ״ו ניסן תשע״ג - שמיני, י״א בעומר
6 Sivan, 5773, Shavuos - ו׳ סיוון תשע״ג, שבועות
7 Sivan, 5773, Shavuos - ז׳ סיוון תשע״ג, שבועות
17 Tammuz, 5773, Seventeenth of Tammuz - י״ז תמוז תשע״ג, שבעה עשר בתמוז
9 Av, 5773, Tishah B'Av - ט׳ אב תשע״ג, תשעה באב
15 Av, 5773, Tu B'Av - ט״ו אב תשע״ג, ט״ו באב

FAQ: Outputting Zmanim for A Different Time Zone With the the Zmanim API

Zmanim API FAQ


Why does the output of zmanim for a different time zone appear incorrect?


One of the common issues encountered by developers using the API is that zmanim generated for a different time zone than the user’s time zone may return output that appears incorrect. For example a user in Lakewood, NJ trying to calculate sunrise for Yerushalayim may attempt to use the following code:

String locationName = "Jerusalem";
double latitude = 31.778; // Har habayis
double longitude = 35.2354;// Har Habayis
double elevation = 0;
TimeZone timeZone = TimeZone.getTimeZone("Asia/Jerusalem");
GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
ZmanimCalendar zc = new ZmanimCalendar(location);
zc.getCalendar().set(2011, Calendar.FEBRUARY, 8);
System.out.println("Sunrise: " + zc.getSunrise());
System.out.println("Sunset: " + zc.getSunset());

While you would expect a sunrise of 6:27:41 AM and sunset of 5:19:19 PM, running this code on a computer anywhere in the Eastern Standard time zone would generate the following time that appears to be 7 hours early:

Sunrise: Mon Feb 07 23:27:41 EST 2011
Sunset: Tue Feb 08 10:19:19 EST 2011

The issue is simple, and the sunrise and sunset returned above are actually accurate. Zmanim are returned by the Zmanim API as a Java Date object that represents a moment in time (stored internally by Java as Unix Time – the number of milliseconds since the January 1, 1970 GMT). Sunrise in Yerushalayim on February 8th actually happens at 11:27:41 PM on February 7th EST. Java is simply outputting the Date as a String formatted to the users default time zone (EST in this example). The user probably intends to output the time in IST – Israel Standard Time (“Asia/Jerusalem” in the Olson database). To do this you have to output the zmanim using a formatter set to use the “Asia/Jerusalem” time zone.

DateFormat zmanimFormat = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");

System.out.println("sunrise: " + zmanimFormat.format(zc.getSunrise()));
System.out.println("sunset:" + zmanimFormat.format(zc.getSunset()));

will output the expected

sunrise: Tue Feb 08 06:27:41 IST 2011
sunset:Tue Feb 08 17:19:19 IST 2011

Below is the full code example.

import net.sourceforge.zmanim.*;
import net.sourceforge.zmanim.util.*;
import java.util.TimeZone;
public class FormatZmanim{
	public static void main(String [] args) {
		String locationName = "Jerusalem";
		double latitude = 31.778; //latitude of Har habayis
		double longitude = 35.2354; //longitude of Har Habayis
		double elevation = 0; //optional elevation
		//use a Valid Olson Database timezone listed in java.util.TimeZone.getAvailableIDs()
		TimeZone timeZone = TimeZone.getTimeZone("Asia/Jerusalem");
		//create the location object
		GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
		ZmanimCalendar zc = new ZmanimCalendar(location); //create the ZmanimCalendar
		zc.getCalendar().set(2011, Calendar.FEBRUARY, 8); //set the date
		DateFormat zmanimFormat = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy"); //Create the formatter
		zmanimFormat.setTimeZone(location.getTimeZone()); //set the formatter's time zone
		System.out.println("sunrise: " + zmanimFormat.format(zc.getSunrise()));
		System.out.println("sunset:" + zmanimFormat.format(zc.getSunset()));

Zmanim API Ported to Cocoa / Objective-C

Port City JavaMoshe Berman completed the 2.0 release of his port of the KosherJava Zmanim API from Java to a Cocoa API using Objective-C. You can see the work in the KosherCocoa project page. The original work on the port dates back to Moshe’s iPhone Ultimate Omer 2 (iTunes link) app. In that app, he ported the minimum amount of code needed to calculate sunset in order to roll the day of the Omer after sunset. With Moshe’s latest check-in at github, he provided a port of a good portion of the API sticking to the basic design of the KosherJava API. The complexZmanimCalendar still remains to be ported, but the majority of zmanim in common use are in the ported ZmanimCalendar. Moshe’s blog post Introducing KosherCocoa 2.0 has additional details. Additional developer notes can be seen in the KosherCocoa wiki page. This port will be a boon to iOS developers who now have a simple way to include zmanim in their iPhone and iPad apps.
Here is some sample code that outputs zmanim to the console.


#import <Foundation/Foundation.h>
#import "ZmanimCalendar.h"

int main (int argc, const char * argv[]){

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    //  Set up the location
    NSString *locationName = @"Lakewood, NJ";
    double latitude = 40.096; //Lakewood, NJ
    double longitude = -74.222; //Lakewood, NJ
    NSTimeZone *timeZone = [NSTimeZone timeZoneForSecondsFromGMT:-18000];

    //  Initialize the Zmanim Calendar
    GeoLocation *geoLocation = [[GeoLocation alloc] initWithName:locationName andLatitude:latitude andLongitude:longitude andTimeZone:timeZone];
    ZmanimCalendar *zmanimCalendar = [[ZmanimCalendar alloc] initWithLocation:geoLocation];

    //  Create a Formatter for the date information
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setTimeZone:timeZone];
    [formatter setDateStyle:NSDateFormatterNoStyle];
    [formatter setTimeStyle:NSDateFormatterMediumStyle];

    NSDate *sunrise = [zmanimCalendar sunrise];
    NSDate *sofZmanShmaMGA = [zmanimCalendar sofZmanShmaMogenAvraham];
    NSDate *sofZmanShmaGRA = [zmanimCalendar sofZmanShmaGra];
    NSDate *sunset = [zmanimCalendar sunset];

    NSLog(@"Today's Zmanim for %@",  [geoLocation locationName]);
    NSLog(@"Sunrise: %@",  [formatter stringFromDate:sunrise]);
    NSLog(@"Sof Zman Shema MGA: %@",  [formatter stringFromDate:sofZmanShmaMGA]);
    NSLog(@"Sof Zman Shema GRA: %@",  [formatter stringFromDate:sofZmanShmaGRA]);
    NSLog(@"Sunset: %@",  [formatter stringFromDate:sunset]);

    [pool drain];
    return 0;

This would output (on February 8th):

Today's Zmanim for Lakewood, NJ
Sunrise: 6:58:43 AM
Sof Zman Shema MGA: 8:59:04 AM
Sof Zman Shema GRA: 9:35:04 AM
Sunset: 5:24:09 PM

Calculating Kiddush Levana Times Using the Zmanim API

Moon Crescent 3 Day LunationCalculating the earliest and latest times for Kiddush Levana has not been part of the KosherJava Zmanim API until now. This is because unlike other zmanim that solely rely on solar calculations that are tied to the Gregorian calendar, times for Kiddush Levanah depend on the Jewish calendar molad (lunar conjunction) computation. With the recent addition of Jewish calendar support to the alpha releases of the KosherJava Zmaim API 1.3, molad calculation was added, allowing for calculation of kidush levana times. Times include the earliest time calculated as 3 and 7 days after the molad. Sof zman kidush levanah includes the Maharil’s opinion that it is calculated as halfway between molad and molad, and the more lenient full 15 days from the molad mentioned by the Mechaber in the Shulchan Aruch. It should be noted that some opinions hold that the Rema who brings down the opinion of the Maharil’s of calculating half way between molad and molad is of the opinion that the Mechaber agrees with him. Also see the Aruch Hashulchan. For additional details on the subject, See Rabbi Dovid Heber’s very detailed writeup in Siman Daled (chapter 4) of Shaarei Zmanim.

Calculating the Molad

Kidush levanah times depend on the time of the molad. The time of the molad announced in shuls on Shabbos Mevarchim is the time of the Molad Emtzai (Average Molad) in Yerushalayim local mean time. This has to be converted to standard time. Standard time uses time zones to unify clock times across a large area. With 360° of longitude around the globe, the world is divided into 24 timezones (one per hour) resulting in timezones that are 15° of longitude each. Har Habayis with a longitude of 35.2354° is 5.2354° away from the 30° longitude line. Multiply the 5.235° by 4 minutes per degree (15° of longitude per hour) to reach 20.94 minutes, or 20 minutes and 56.496 seconds (5.235 * 4 = 20.94). This time is subtracted from the local molad time to arrive at Standard time. Since the time of the molad is at the same instant globally (unlike zmanim such as sunrise that depend on a person’s location), converting this to a user’s local time involves simply calculating the time difference between the time in Yerushalayim and your location. If daylight savings time is in use, this has to be added to the calculation. Java date formatting classes do this calculation on Date objects without forcing the developer to do any calculations.

Calculating the Start and End of Kiddush Levana Times

The JewishCalendar class contains the methods for claculating these zmanim. Calculating Tchilas Zman Kiddush Levana (the earliest time Kiddush Levana can be said) is done by adding 3 days or 7 days to the molad time. Sof Zman Kiddush Levana (the latest time Kiddush Levana can be said) is either the time between molad and molad calculated by adding 14 days, 18 hours, 22 minutes and 1.666 seconds to the molad (half the 29 days, 12 hours, 44 minutes and 1 chelek (3.333 seconds)), or by adding 15 days to the molad.

Using the Zmanim API Calculate Molad Based Times

Here is sample code for calculating various kiddush levana times for anywhere in the world for Shevat 5729 (1969). Since formatting classes requires a timezone for proper formatting, the simple code below assumes that you are looking for the time in your local timezone. If you want the time for a timezone other than the one your computer is in, set the SimpleDateFormat.setTimeZone() to the timezone you wish to display the times for.

int year = 5729;
int month = JewishDate.SHEVAT;
Date tchilas3Days = JewishCalendar.getTchilasZmanKidushLevanah3Days(year, month);
Date tchilas7Days = JewishCalendar.getTchilasZmanKidushLevanah7Days(year, month);
Date sofZmanBetweenMoldos = JewishCalendar.getSofZmanKidushLevanahBetweenMoldos(year, month);
Date sofZmanKidushLevanah15Days = JewishCalendar.getSofZmanKidushLevanah15Days(year, month);
SimpleDateFormat sdf = new SimpleDateFormat("MMM dd, yyyy 'at' HH:mm:ss z");
System.out.println("Tchilas Zman Kiddush Levana 3 Days: " + sdf.format(tchilas3Days));
System.out.println("Tchilas Zman Kiddush Levana 7 Days: " + sdf.format(tchilas7Days));
System.out.println("Sof Zman Kiddush Levana Between Moldos: " + sdf.format(sofZmanBetweenMoldos));
System.out.println("Sof Zman Kiddush Levana 15 Days: " + sdf.format(sofZmanKidushLevanah15Days));

this will output the following in an EST timezone.

Tchilas Zman Kiddush Levana 3 Days: Jan 21, 1969 at 06:06:29 EST
Tchilas Zman Kiddush Levana 7 Days: Jan 25, 1969 at 06:06:29 EST
Sof Zman Kiddush Levana Between Moldos: Feb 02, 1969 at 00:28:31 EST
Sof Zman Kiddush Levana 15 Days: Feb 02, 1969 at 06:06:29 EST

Kiddush Levana Times During Daylight Hours

As you can see, all of these times are at night (After tzais 72 and prior to Alos 72 minutes in Montreal). Many times, these calculations will result in times that are during daylight hours when Kidush Levana can’t be said. When using the API and calculating the time for the tchilas zman kiddush levana and the time is during daylight hours, the earliest time should be tzais the following night. When the calculated time of sof zman kiddush levana is during daylight hours, the time posted should be alos on the previous night. The API may at some point support a method of automatically calculating this.

Calculating Erev Pesach Zmanim

MatzahThe Zmanim API did not have dedicated zmanim to claculate the Erev Pesach zmanim of sof zman achilas chametz (the latest time one can eat chametz), and sof zman biur chametz (the latest time to burn chametz) till the April 14 check in to the KosherJava Zmanim Project GitHub repository. The latest time for eating chametz is at the end of the 4th hour of the day. This corresponds to sof zman tfila. The API has about 12 of those, so that does not require any special programming, but to help developers who are unaware of how they work I created 3 wrapper getSofZmanAchilasChametz methods (getSofZmanAchilasChametzGRA(), getSofZmanAchilasChametzMGA72Minutes() and getSofZmanAchilasChametzMGA16Point1Degrees()) calling the 3 most commonly used getSofZmanTfila methods (getSofZmanTfilaGRA(), getSofZmanTfilaMGA72Minutes() and getSofZmanTfilaMGA16Point1Degrees()). For example here is the exact code used in getSofZmanAchilasChametzGRA()

public Date getSofZmanAchilasChametzGRA() {
	return getSofZmanTfilaGRA();

The API itself is very flexible, and as long as you know the calculation of the zman, you can easily calculate it. For example, to calculate sof zman biur chametz according to the GR"A, the time would be 5 shaos zmaniyos after sunrise. Using the Zmanim API this would be coded as:

Date SofZmanBiurChametzGra = getTimeOffset(getSeaLevelSunrise(), getShaahZmanisGra() * 5);

The exact code used in the API is:

public Date getSofZmanBiurChametzGRA() {
	return getTimeOffset(getSeaLevelSunrise(), getShaahZmanisGra() * 5);

Developers who want to use the current API to generate these zmanim can use the following sample as a guide.

String locationName = "Lakewood, NJ";
double latitude = 40.09596; //Lakewood, NJ
double longitude = -74.22213; //Lakewood, NJ
double elevation = 0; //optional elevation
TimeZone timeZone = TimeZone.getTimeZone("America/New_York");
GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
ComplexZmanimCalendar czc = new ComplexZmanimCalendar(location);
czc.getCalendar().set(Calendar.YEAR, 2011);
czc.getCalendar().set(Calendar.MONTH, Calendar.APRIL);
czc.getCalendar().set(Calendar.DAY_OF_MONTH, 18);
Date graAchilas = czc.getSofZmanTfilaGRA();
Date graBiur = czc.getTimeOffset(czc.getSeaLevelSunrise(), czc.getShaahZmanisGra() * 5);
Date mga72Achilas = czc.getSofZmanTfilaMGA72Minutes();
Date mga72Biur = czc.getTimeOffset(czc.getAlos72(), czc.getShaahZmanisMGA() * 5);
Date mga16Achilas = czc.getSofZmanTfilaMGA16Point1Degrees();
Date mga16Biur = czc.getTimeOffset(czc.getAlos16Point1Degrees(), czc.getShaahZmanis16Point1Degrees() * 5);
System.out.println("Erev Pesach Zmanim for " + locationName);
System.out.println("Sof Zman Achilas Chametz GRA: " + graAchilas);
System.out.println("Sof Zman Biur Chametz GRA: : " + graBiur);
System.out.println("Sof Zman Achilas Chametz MGA 72 Minutes: " + mga72Achilas);
System.out.println("Sof Zman Biur Chametz MGA 72 Minutes: " + mga72Biur);
System.out.println("Sof Zman Achilas Chametz MGA 16.1 Deg: " + mga16Achilas);
System.out.println("Sof Zman Biur Chametz MGA 16.1 Deg: " + mga16Biur);

this would output

C:\path\to\code>javac ErevPesachZmanim.java

C:\path\to\code>java ErevPesachZmanim

Erev Pesach Zmanim for Lakewood, NJ
Sof Zman Achilas Chametz GRA: Mon Apr 18 10:42:42 EDT 2011
Sof Zman Biur Chametz GRA: : Mon Apr 18 11:49:39 EDT 2011
Sof Zman Achilas Chametz MGA 72 Minutes: Mon Apr 18 10:18:42 EDT 2011
Sof Zman Biur Chametz MGA 72 Minutes: Mon Apr 18 11:37:39 EDT 2011
Sof Zman Achilas Chametz MGA 16.1 Deg: Mon Apr 18 10:13:56 EDT 2011
Sof Zman Biur Chametz MGA 16.1 Deg: Mon Apr 18 11:35:18 EDT 2011