NOAA Fixes Solar Calculator

When comparing the results of the KosherJava NOAA algorithm to the output of NOAA’s new Solar Calculator almost two years ago, a discrepancy was encountered between the two. There was no discrepancy compared to the output of the old NOAA calculator. The NOAA code is an implementation of the accurate Jean Meeus algorithm for solar time calculations, and the KosherJava code is a Java port of this algorithm. While attempting to debug the issue, I turned to Pinny Markowitz who ported the KosherJava library to both Ruby and Python. He was able to trace the issue to what seemed to be a small accuracy adjustment missing in the noon calculation on the new NOAA implementation. Based on Pinny’s analysis, the old implementation seemed correct, but without confirmation from the NOAA developers this was not a certainty. We reported the issue to NOAA for clarification, and after an almost two-year delay, the NOAA development team confirmed and corrected the bug. After NOAA’s fix there is no longer any discrepancy. The fix can be seen in line 342 of the NOAA JavaScript file, where a half day adjustment is made in the noon time calculation. This bug was never present in the KosherJava library, or other language ports of the KosherJava code, since our code was based on the original NOAA code.

Zmanim API Ported to Cocoa / Objective-C

Moshe 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.

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;
}

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

KosherJava Zmanim API Released Under the LGPL License

LGPL 2.1Until this point the KosherJava Zmanim API has been released under the GPL V2.0 open source license. This had the effect of forcing any application written using the library to release it’s source code under the same license. Being that the Zmanim API is a library, the LGPL is a more appropriate license. The LGPL allows developers to use the KosherJava Zmanim API, yet keep their application code closed source. Only changes to the API itself (such as ports to different languages) would have to be released as open source. I had in the past on request released the source under the LGPL (the Zmanim API .NET port has already been released under the LGPL with my permission), and with the recent 3/27/2011 SVN checkin I formally changed the Java Zmanim API license to the LGPL 2.1 (not the newer LGPL 3.0). The next 1.3.0 release will be the first formal release under the LGPL. In one case the change to the license required permission from developer who wrote code used by the Zmanim API, and this was done.

Zmanim API Ported to .NET (C#)

Yitzchok ported the Zmanim API from Java to a .NET API using C#. The Zmanim .NET project was released under the LGPL 2.1. This is a change from the GPL used by the Java API, something that may change shortly. Also part of the project was the creation of a C# version of the Zmanim CLI, matching Moshe Wagner’s Java Zmanim CLI. When developing the project, Yitzchok created the ZmanimTest JUnit test case class to confirm that the C# port output matched the Java API. I will likely add this to the core Zmanim API in the near future. The port currently relies on IKVM assemblies as can be seen in the Java references in the code sample below, mostly because of the lack of a native .NET equivalent of the Java TimeZone class. Yitzchok also created some examples of the use of the Zmanim .NET API that will be of help to developers. Below are two of the simpler examples in C# and VB.NET demonstrating a very simple use of the API to output zmanim from the console.

C#

using Zmanim.TimeZone;
using Zmanim.TzDatebase; //in Zmanim.TzDatebase.dll assembly
using Zmanim.Utilities;

namespace Zmanim.Samples.Console
{
    class Program
    {
        static void Main(string[] args)
        {
            string locationName = "Lakewood, NJ";
            double latitude = 40.09596; //Lakewood, NJ
            double longitude = -74.22213; //Lakewood, NJ
            double elevation = 0; //optional elevation
            ITimeZone timeZone = new OlsonTimeZone("America/New_York");
            GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
            ComplexZmanimCalendar zc = new ComplexZmanimCalendar(location);
            //optionally set it to a specific date with a year, month and day
            //ComplexZmanimCalendar zc = new ComplexZmanimCalendar(new DateTime(1969, 2, 8), location);

            System.Console.WriteLine("Today's Zmanim for " + locationName);
            System.Console.WriteLine("Sunrise: " + zc.GetSunrise()); //output sunrise
            System.Console.WriteLine("Sof Zman Shema MGA: " + zc.GetSofZmanShmaMGA()); //output Sof Zman Shema MGA
            System.Console.WriteLine("Sof Zman Shema GRA: " + zc.GetSofZmanShmaGRA()); //output Sof Zman Shema GRA
            System.Console.WriteLine("Sunset: " + zc.GetSunset()); //output sunset

            System.Console.WriteLine("Press enter to exit.");
            System.Console.ReadLine();
        }
    }
}

VB.NET

mports Zmanim.TzDatebase 'in Zmanim.TzDatebase.dll assembly
Imports Zmanim.Utilities
Imports Zmanim.TimeZone

Module Module1

    Sub Main()
        Dim locationName As String = "Lakewood, NJ"
        Dim latitude As Double = 40.09596 'Lakewood, NJ
        Dim longitude As Double = -74.22213 'Lakewood, NJ
        Dim elevation As Double = 0 'optional elevation
        Dim timeZone As ITimeZone = New OlsonTimeZone("America/New_York")
        Dim location As New GeoLocation(locationName, latitude, longitude, elevation, timeZone)
        Dim zc As New ComplexZmanimCalendar(location)
        'optionally set it to a specific date with a year, month and day
        'Dim zc As New ComplexZmanimCalendar(New DateTime(1969, 2, 8), location)
        System.Console.WriteLine("Today's Zmanim for " & locationName)
        System.Console.WriteLine("Sunrise: " & zc.GetSunrise().ToString)
        'output sunrise
        System.Console.WriteLine("Sof Zman Shema MGA: " & zc.GetSofZmanShmaMGA().ToString)
        'output Sof Zman Shema MGA
        System.Console.WriteLine("Sof Zman Shema GRA: " & zc.GetSofZmanShmaGRA().ToString)
        'output Sof Zman Shema GRA
        System.Console.WriteLine("Sunset: " & zc.GetSunset().ToString)
        'output sunset
        System.Console.WriteLine("Press enter to exit.")
        System.Console.ReadLine()

    End Sub

End Module

The current Zmanim .NET TODO list for the project includes:

  • Remove dependency to Java (IKVM assemblies)
  • The API should follow the .NET guidelines
  • Make it Linq friendly
  • Add examples how to use this project in a ASP.NET MVC site and WPF Application
  • Try to get it to work on Silverlight