According to almost all opinions, the halachic Dateline is not determined by what the locals call “Saturday” and therefore, the fact that Samoa changes the Dateline does not change when we keep Shabbos.

Location of the Halachic Date Line

1. The Chazon Ish quoting the Kuzari and the Baal Hamaor who state that the date line is 90° east of the Har Habayis.
2. Rabbi Yechiel Michel Tucazinsky (author of the Gesher Hachaim) who wrote the היומם בכדור הארץ Hayomam Bekadur Haaretz stating his opinion that the date line is 180° east (or west) of Har Habayis. Among those agreeing with this opinion is Rabbi Elyashiv. Since this line is exactly halfway around the world from Yerushalayim, a person on different sides of this line will face different directions when davening (using the rhumb line method). A person located west of the line will daven westward, and a person east of the line will daven eastwards. See the Bearing to Yerushalayim Map for a location along this line (the green line). Click on the blue pushpin in the map (below the green line) for additional information on the antipodal point of the Har Habayis.
3. Rabbi Menachem Mendel Kasher in his קו התאריך הישראלי Kav Hattarich Hayisraeli is of the opinion that the international dateline is used. Among those agreeing with this opinion was Rabbi Isser Zalman Meltzer.

How the Map Works

• Tahania Atoll, a small atoll in French Polynesia that is intersected by Rabbi Tucazinsky’s line. To the south of this point is the island of Rapa Iti. There is an interesting Halachic phenomenon at this location with Kiddush Levana in December 2027. See Rabbi Heber’s Sefer Shaarei Zemanim שערי זמנים. Rabbi Heber graciously allowed me to post סימן ד׳ – קונטרס זמן קידוש לבנה of the Shaarei Zemanim here. The discussion of Kiddush Levana on Rapa Iti appears on page 14 of the pdf which is page 32 in the sefer.
• Ikema Island is intersected by the Baal Hamaor’s line. According to the Chazon Ish “Graira” covers the entire Ikema Island, but would not (according to Rabbi Dovid Heber of the Star-K) extend over the bridge to Miyakojima Island.
• The line of the Baal Hamaor runs through Changchun, China a city of 7 million. According to the Chazon Ish, “Graira” would mean the line does not split the city.
• Are islands on Lake Argyle, a 100 miles inland but with a river leading to the ocean included in Graira using the Chazon Ish’s line? According to Rabbi Heber the river would “not ruin graira”, and such islands would be included. Would you say the same thing for French and Phillip Islands near Melbourne, Australia? Rabbi Heber is of the opinion that one should be machmir on these islands.
• Clarity about exactly what parts of the Philippines are on the other side of the date line. Some say it is better not to travel to the Philippines due to questions of the placement of the Baal Hamaor/Chazon Ish line, but the dateline map clarifies ambiguities about this part of the world.

Additional Reading

• Taarich Yisrael תאריך ישראל by Rabbi Yisroel Taplin
• Yisroel Vehazmanim ישראל והזמנים Vol II Chapter 13 קו התאריך by Rabbi Yisroel Dovid Harfenes
• A Traveler’s Guide To The International Dateline by Rabbi Dovid Heber.
• The International dateline and Related Issues by David Pahmer.
• קו התאריך בהלכה in the Hebrew Wikipedia
• פולמוס השבת ביפן in the Hebrew Wikipedia
• Various articles in the Haoros journal

• Android Zmanim (Android)
• YahrtzeitZmanim (Android)
• Zmanim (Windows Phone)
• Siddur (RustyBrick) (iPhone)
• mMinyan (for both Android and iPhone)
• ZmanimMinder (Android)
• Find a Minyan (Android)
• Siddur (OKTM) (Android)
• Jewish Cal (iPhone)
• Smart Siddur (Android)
• Zmanim (iPhone)
• Ultimate Omer 2 (iPhone)
• Sefirat Haomer (Android)
• Shabbat Shalom (Android and iPhone)
• Daka Tora (Android) an app for Jewish soldiers
• Mincha Alerts (iPhone)

Question:

Answer:

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());

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

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

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

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

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()));
	}
}

• A number of additional zmanim in the More Zmanim tab, including tchilas and sof zman kiddush levana (if they occur on that day)
• A link to download a 12 month Zmanim calendar directly from the map (using the same spreadsheet used in the Zmanim Calendar Generator). Clicking on the link from the Zmanim tab will generate a calendar with most typically used zmanim, while clicking on the link in the More Zmanim tab will download the full set of zmanim. These are available as the Calendar Type option in the Zmanim Calendar Generator
• Increased use of jQuery and jQuery UI for formatting the zmanim tables to better match the site look & feel
• Refactoring to make the code more robust and slightly more maintainable
• Timezones for all of Israel now display the timezone of Asia/Jerusalem as opposed to the Asia/Gaza returned for parts of Israel by the GeoNames TimeZone web service

• v3 no longer supports tabbed info windows, so the tabs are now implemented using jQuery UI
• Renaming of a number of classes and functions such as GLatLng to LatLng
• A number of functions that were part of API v2 were removed in v3. One example is the removal of radians in the LatLng that had been available as GLatLng.latRadians(). These missing functions required for the direction to Yerushalayim calculations are now supported in the Zmanim Map using prototypes

Zmanim.m

#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;
}

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 the Molad

Calculating the Start and End of Kiddush Levana Times

Using the Zmanim API Calculate Molad Based Times

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));

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

public Date getSofZmanAchilasChametzGRA() {
	return getSofZmanTfilaGRA();
}

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

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

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);

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

Question:

Answer: