Zmanim API 2.3.0 Released


The KosherJava Zmanim API version 2.3.0 was released on Dec 7th, 2021 ג׳ טבת תשפ״ב in Maven and GitHub. While there have been numerous releases over the years, this is the first release-related post since the v1.3.0 release in 2013. If you have not updated since that time, you can expect some changes. The most significant changes (besides a lot of new functionality) are the simple to fix breaking changes listed below.

New in Version 2.3.0

The list of significant changes in this and previous releases can be seen in the KosherJava Zmanim API changelog.

Breaking Changes since v1.3

Rav Moshe Feinstein’s Zmanim Added to the KosherJava Zmanim API


Rav Moshe Feinstein is of the opinion that chatzos is at a fixed time all year round and is calculated based on the location’s longitude (in Lakewood, NJ it is at 11:56am / 12:56pm during DST). See Igros Moshe Orach Chaim vol 4 no. 20 for more details. The Aruch Hashulchan also calculates chatzos at a fixed time all year. Rav Moshe also bases other zmanim calculations on this fixed local chatzos. As opposed to calculating shaaos zmaniyos from beginning to the end of a day, Rav Moshe calculates a number of zmanim based on half of the day starting or ending at fixed local chatzos (see Igros Moshe Orach Chaim vol 1, no. 23). These zmanim are used in Mesivta Tiferet Yerushalayim (MTJ), Yeshiva of Staten Island and Camp Yeshiva of Staten Island. Code to calculate these Rav Moshe zmanim is now part of the latest v2.3.0 release of the KosherJava Zmanim API.
The following new zmanim are now included in the API:

Sample Usage

For developers, here is sample code that calculates the new zmanim. This should allow many zmanim apps to add Rav Moshe Feinstein’s zmanim with very little effort.

String locationName = "145 E Broadway, New York, NY";
double latitude = 40.7138;
double longitude = -73.9913;
double elevation = 11;
TimeZone timeZone = TimeZone.getTimeZone("America/New_York");
GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
ComplexZmanimCalendar czc = new ComplexZmanimCalendar(location);
czc.getCalendar().set(1986, Calendar.MARCH, 23); //Rav Moshe's petirah
System.out.println("Sof zman shma alos 18° to fixed local chatzos: " + czc.getSofZmanShmaMGA18DegreesToFixedLocalChatzos());
System.out.println("Sof zman shma alos 16.1° to fixed local chatzos: " + czc.getSofZmanShmaMGA16Point1DegreesToFixedLocalChatzos());
System.out.println("Sof zman shma alos 90 to fixed local chatzos: " + czc.getSofZmanShmaMGA90MinutesToFixedLocalChatzos());
System.out.println("Sof zman shma alos 72 to fixed local chatzos: " + czc.getSofZmanShmaMGA72MinutesToFixedLocalChatzos());
System.out.println("Sof zman shma sunrise to fixed local chatzos: " + czc.getSofZmanShmaGRASunriseToFixedLocalChatzos());
System.out.println("Sof zman tfila sunrise to fixed local chatzos: " + czc.getSofZmanTfilaGRASunriseToFixedLocalChatzos());
System.out.println("Mincha gedola 30 minutes after fixed local chatzos: " + czc.getMinchaGedolaGRAFixedLocalChatzos30Minutes());
System.out.println("Mincha katana fixed local chatzos to sunset: " + czc.getMinchaKetanaGRAFixedLocalChatzosToSunset());
System.out.println("Plag hamincha fixed local chatzos to sunset: " + czc.getPlagHaminchaGRAFixedLocalChatzosToSunset());
System.out.println("Tzais 50 minutes after sunset: " + czc.getTzais50());

Calculating other fixed local chatzos based zmanim not included in the library (and not necessarily endorsed by this shitta) are very simple with the generic getFixedLocalChatzosBasedZmanim(Date startOfHalfDay, Date endOfHalfDay, double hours) method built to simplify calculating these zmanim. Here are a few examples.

//4 hours into a day based on half the day from alos 18° to fixed local chatzos
System.out.println("Sof zman tfila 18° to fixed local chatzos: " + czc.getFixedLocalChatzosBasedZmanim(getAlos18Degrees(), getFixedLocalChatzos(), 4); 
//plag hamincha based on the second half of the day starting at fixed local chatzos and ending 50 minutes after sunset
System.out.println("Plag hamincha fixed local chatzos to tzais 50 minutes: " + czc.getFixedLocalChatzosBasedZmanim(getFixedLocalChatzos(), getTzais50(), 4.75); 

I would like to thank Avraham David Gelbfish who requested this addition and provided instructions on the proper calculations used by these yeshivos in calculating the zmanim.

The Yereim’s Bein Hashmashos

Rabbi Eliezer of Metz (known by his acronym The רא״ם Re’em), a disciple of Rabbeinu Tam, in his Sefer Yereim ספר יראים chapter 274, states that bein hashmashos starts the time it takes to walk three quarters of a mil before sunset, and ends at sunset.

פירוש משתשקע החמה דר׳ יהודה ור׳ נחמיה משמתחלת לשקוע שנוטה מעט ומכירים העולם שרוצה להכנס בעובי הרקיע … ולשון משתשקע משמע הקדמה … וכן נראה לי עיקר דמשתשקע החמה הוא קודם שקיעת החמה דעולא ולא כדברי רבינו יעקב … ואין להקפיד על צאת הככבים … אע״ף שאין הכוכבים נראים … שלילה גמור הוא כפירושי.

The Yereim’s opinion is brought down by other Rishonim including the Mordechai and Rav Alexander Suslin HaKohen in his Sefer Agudah. The Yereim is mentioned by the Bach as a reason for the minhag of starting Shabbos early. The Yereim’s times are not brought down by the poskim lehalacha.

The Time to Walk a Mil

The time to walk a mil is based on the Gemara in Pesachim 93b – 94a. The time ranges in the poskim and includes 18, 22.5 and 24 minutes. Three quarters of these mil times would be 13.5, 16.875 and 18 minutes. It should be noted that the Yereim is of the opinion that a mil is 24 minutes. The above mentioned Mordechai who quoted the Yereim is also of the same opinion. We will hopefully discuss in detail the various opinions on the time to walk a mil in a future article.

The Addition of the Yereim’s Times to the KosherJava Zmanim Library

As of the 2.1.0 release of the KosherJava zmanim library, the Yereim’s bein hashmashos times have been added to the KosherJava zmanim library/API. There are six variants of these zmanim that were added. These include the three exact minute offsets mentioned above, as well as the conversion of these three times to degrees (elevation angle, or solar zenith angle). The only prior degree based time for the Yereim that I am aware of is in Rabbi Yedidya Manat’s Zmanei Halacha Lema’aseh (זמני ההלכה למעשה מהרב ידידיה מנת). The Zmanei Halacha Lema’aseh charts calculate bein hashmashos in degrees based on the 18 minute (3/4 of a 24 minute mil, see p. 27 in the 4th ed. published in 2005), but does not clarify the degrees used. At Rabbi Yaakov Shakow’s recommendation, I used the refraction value of 31/60 or 0.516° that exists in Israel, as opposed to the global average of 0.566°. This more stringent refraction is mentioned in the Zmanei Halacha Lema’aseh (p. 11) and used in the Luach Itim Lebinah. I also slightly rounded the times. These small tweaks resulted in a trivial maximum 19 second chumra vs the non-rounded global average refraction. The resulting degrees of elevation angle for the Yereim’s bein hashmashos are 2.1°, 2.8° and 3.05°. Solar zenith angles are traditionally calculated using the sun’s position without adjusting for refraction and without accounting for the solar radius (i.e. it is the position of the center of the sun in a vacuum). This does not impact the calculated time, it is simply the convention used. In the upcoming 8th edition of the Rabbi Yehuda Burstein’s זמנים כהלכתם / Zmanim Kehilchasam he mentions that

הזמן הנ״ל של 18 דקות לפני השקיעה המישורית הוא הזמן רק במרכז א״י ביום הבינוני כנ״ל, ובכל מקום בכל יום מחשבין זאת לפי שיטת המעלות, דהיינו דבודקים כמה מעלות מעל האופק נמצאת השמש במרכז א״י ביום הבינוני 18 דקות לפני השקיעה המישורית, ואותו מספר מעלות של השמש מעל האופק בכל מקום בכל יום הוא הזמן של ״היראם״. ועוד יש להוסיף זמן ל״תוספת שבת״, ובזה יוצא ידי כל שיטות הראשונים ואשרי חלקו.

A future article will address the proper date to use for converting minute based times to degrees below (or above) the horizon and show how to use the KosherJava Zmanim code to calculate this.
I would like to thank Rabbi Yaakov Shakow for his help and suggestions.

Sample Code

Below are code examples for all six variants of the Yereim’s Bein Hashmashos (spelled BainHashmashos in the code).

GeoLocation yerushalayim = new GeoLocation("Jerusalem, Israel", 31.778, 35.2354, 0, TimeZone.getTimeZone("Asia/Jerusalem"));
ComplexZmanimCalendar czc = new ComplexZmanimCalendar(yerushalayim);
Date bh18Min = czc.getBainHasmashosYereim18Minutes();
Date bh3Pt05Deg = czc.getBainHasmashosYereim3Point05Degrees();
Date bh16Pt875Min = czc.getBainHasmashosYereim16Point875Minutes();
Date bh2Pt8Deg = czc.getBainHasmashosYereim2Point8Degrees();
Date bh13Pt5Min = czc.getBainHasmashosYereim13Point5Minutes();
Date bh2Pt1Deg = czc.getBainHasmashosYereim2Point1Degrees();

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd h:mm:ss a z"); //set the output format
sdf.setTimeZone(czc.getGeoLocation().getTimeZone()); //set the formatter's time zone
System.out.println("Bein Hashmashos 18 min:     " + sdf.format(bh18Min));
System.out.println("Bein Hashmashos 3.05°:      " + sdf.format(bh3Pt05Deg));
System.out.println("Bein Hashmashos 16.875 min: " + sdf.format(bh16Pt875Min));
System.out.println("Bein Hashmashos 2.8°:       " + sdf.format(bh2Pt8Deg));
System.out.println("Bein Hashmashos 13.5 min:   " + sdf.format(bh13Pt5Min));
System.out.println("Bein Hashmashos 2.1°:       " + sdf.format(bh2Pt1Deg));

The output of the above code (assuming that the calendar was set to March 16, 2020).

Bein Hashmashos 18 min:     2020-03-16 5:29:58 PM IST
Bein Hashmashos 3.05°:      2020-03-16 5:29:40 PM IST
Bein Hashmashos 16.875 min: 2020-03-16 5:31:05 PM IST
Bein Hashmashos 2.8°:       2020-03-16 5:30:51 PM IST
Bein Hashmashos 13.5 min:   2020-03-16 5:34:28 PM IST
Bein Hashmashos 2.1°:       2020-03-16 5:34:09 PM IST

KosherJava Zmanim Library Package Name and Build Process Update


The KosherJava zmanim library originally went live in 2004. There was an existing C/C++ zmanim project by Ken Bloom hosted on SourceForge (that was at the time the equivalent of what GitHub is today). The Java package structure name net.sourceforge.zmanim was based on the one used by Ken’s project (despite not being hosted there), and remained that way for 16 years.
On August 3, 2020, Eli Julian modernized the library’s build process from the previously used Ant, to Maven & Gradle. This change simplified the workflow for many developers using the zmanim API. As part of the change, the package name was updated to com.kosherjava.zmanim. The KosherJava zmanim Maven / Gradle artifacts are available at the KosherJava zmanim Maven Central page. A direct Jar download is available at Maven Central (see the KosherJava Downloads page for instructions). The old code was branched into zmanim-1.5 and will allow people who do not want to upgrade to continue to use the old structure (and Ant build process) while continuing to receive emergency bug fixes. This will allow the codebase to use more modern Java language features, without impacting users who want to remain on the legacy code. The new code has a minimum Java 8 requirement (a version released in March 2014). Releases based on the new build process will use SemVer (Semantic Versioning) to make things simpler for developers.
The upgraded build process also allowed automated GitHub’s CodeQL vulnerability scanning for the KosherJava Zmanim project.
You can add the KosherJava zmanim library as a Maven or Gradle dependency. For Maven add the following to your pom.xml.

<dependency>
  <groupId>com.kosherjava</groupId>
  <artifactId>zmanim</artifactId>
  <version>2.0.3</version>
</dependency>

For Gradle, add the following to your build.gradle file.

implementation group: 'com.kosherjava', name: 'zmanim', version: '2.0.3'

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.