Question:

How do I calculate the בעל התניא 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.
Update on Dec 14, 2018 – ו׳ טבת תשע״ט: This article was superseded with the more recent and corrected article Baal Hatanya’s Zmanim Added to KosherJava Zmanim Library.

Using the Zmanim API 1.3.0 Jewish Calendar Code

The 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.format(jd));
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
```

Output:

```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(hdf.formatParsha(jd));
hdf.setHebrewFormat(true);
System.out.println(hdf.formatParsha(jd));
jd.back();
System.out.println("Parsha on Friday [" + hdf.formatParsha(jd) + "]"); //no Parsha output on a non Shabbos
jd.setJewishDate(5773, JewishDate.TAMMUZ, 28); //double parsha
System.out.println(hdf.formatParsha(jd));
```

Output:

```Tzav
צו
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
System.out.println(hdf.formatRoshChodesh(jd));
}
hdf.setHebrewFormat(true);
System.out.println(hdf.formatRoshChodesh(jd));
jd.forward();// roll calendar to second day of Nisan
System.out.println("output[" + hdf.formatRoshChodesh(jd) + "]"); //no output for Rosh Chodesh Formatting
```

Output:

```Rosh Chodesh Nissan
ראש חודש ניסן
output[]
```

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"
```

Output:

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

Chanukah

```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
```

Output:

```25 Kislev, 5772
1
Chanukah 1
א׳
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();
hdf.setHebrewFormat(true);
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);
jc.forward();
}
```

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
...
```

Zmanim API 1.3.0 Released

The Zmanim API version 1.3.0 was released on March 4th, 2013 כ״א אדר תשע״ג. Various changes in the new release VS the previous version 1.2.1 that was released in May 2010 can be seen below. This release includes beta support for Jewish Calendar calculations as well as a number of updated zmanim and refactored code. The Jewish Calendar support in the Zmanim API is based on Avrom Finkelstien’s HebrewDate project released in 2002. Unlike the Zmanim code, the Jewish calendar interfaces may change significantly in the future (see Jay Gindin’s various changes that may make it into this API) and should therefore be considered beta.

Changes in the Zmanim API 1.3.0 release

Changes since March 23, 2011 have been in SVN and detailed changes can be seen there.

KosherJava Zmanim API Powering Many Mobile Apps

In the past I posted about Android Zmanim, Jay Gindin’s open source Android zmanim project that uses the KosherJava Zmanim API. The fact that Android development uses Java natively means that it is very simple for Android developers to include zmanim in their apps. Since that time there have been a number of other applications (including iPhone apps) using the code. Moshe’s KosherCocoa Obj-C port of the KosherJava Zmanim API will probably result in additional iPhone apps that use the API. Yitzchok’s older Zmanim .NET port of the KosherJava Zmanim API also opened the door for Windows Phone zmanim applications as well (Ari Polski’s Zmaim app already uses it, and there are others in the works). I may post additional details about some of them in the future, including an updated post about Jay’s latest Android Zmanim release. I am aware of the following mobile applications that use the KosherJava Zmanim API.

There are also a few secular apps that are non-zmanim specific that use the API for sunrise and sunset calculations. One that I know of is Jeffrey Blattman’s Dawn to Dusk Widget, and I know that there are some photography apps that use it for sunrise/set calculations as well. There are likely more that I have missed, and a few that are in active development but unreleased. If you are aware of any missed apps, please let me know.

Question:

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");
zmanimFormat.setTimeZone(location.getTimeZone());

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 com.kosherjava.zmanim.*;
import com.kosherjava.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()));
}
}
```