Zmanim Project

Created by KosherJava on June 22, 2005 - ט"ז סיון תשס"ה | Tagged as: Uncategorized

The Zmanim (”times” referring to the calculations of time that govern the start and end time of Jewish prayers and holidays) project is a Java API for generating zmanim from within Java programs. If you are a non programmer, this means that the software created by the project is a building block of code to allow other programmers to easily include zmanim in their programs. The basis for most zmanim in this class are from the sefer Yisroel Vehazmanim by Rabbi Yisroel Dovid Harfenes. The code available under the GPL license can now be downloaded.
Please note: due to atmospheric conditions (pressure, humidity and other conditions), calculating zmanim accurately is very complex. The calculation of zmanim is dependant on Atmospheric refraction (refraction of sunlight through the atmosphere), and zmanim can be off by up to 2 minutes based on atmospheric conditions. Inaccuracy is increased by elevation. It is not the intent of this API to provide any guarantee of accuracy. See Using a Digital Terrain Model to Calculate Visual Sunrise and Sunset Times for additional information on the subject.

How to Use the API

Information on how to use the API can be found on the How to Use the API page as well as by reading the JavaDocs

Zmanim Calendar Generator

A sample use of the API can be seen in the calendar generator. This uses the Zmanim API to generate an annual Zmanim calendar in an Excel spreadsheet. Since this is a demo of the API, the calendar is generated using All (about 102 currently) possible zmanim that the API can generate.

List of Zmanim Supported by the API

The API currently can generate about 102 zmanim. Explanation of most of these can be seen by browsing the JavaDocs. You can link to the documentation of the specific zmanim from the links below.

  1. Alos 120
  2. Alos 120 Zmanis
  3. Alos 26º
  4. Alos 96
  5. Alos 19.8º
  6. Alos 90
  7. Alos 90 Zmanis
  8. Alos 18º
  9. Alos 16.1º
  10. Alos 72
  11. Alos 72 Zmanis
  12. Alos 60
  13. Misheyakir 10.2º
  14. Misheyakir 11º
  15. Misheyakir 11.5º
  16. Sunrise
  17. Sof Zman Shma GRA
  18. Sof Zman Shma MGA 120
  19. Sof Zman Shma MGA 16.1º
  20. Sof Zman Shma MGA 19.8º
  21. Sof Zman Shma MGA 72
  22. Sof Zman Shma MGA 72 Zmanis
  23. Sof Zman Shma MGA 90
  24. Sof Zman Shma MGA 90 Zmanis
  25. Sof Zman Shma MGA 96
  26. Sof Zman Shma MGA 96 Zmanis
  27. Sof Zman Shma MGA Alos to Sunset
  28. Sof Zman Shma MGA Alos to Tzais Geonim
  29. Sof Zman Shma 3 Hours Before Chatzos
  30. Sof Zman Shma 3 Hours Before Fixed Local Chatzos
  31. Sof Zman Shma Kol Eliyahu
  32. Sof Zman Tfila GRA
  33. Sof Zman Tfila MGA 120
  34. Sof Zman Tfila MGA 16.1º
  35. Sof Zman Tfila MGA 19.8º
  36. Sof Zman Tfila MGA 72
  37. Sof Zman Tfila MGA 72 Zmanis
  38. Sof Zman Tfila MGA 90
  39. Sof Zman Tfila MGA 90 Zmanis
  40. Sof Zman Tfila MGA 96
  41. Sof Zman Tfila MGA 96 Zmanis
  42. Sof Zman Tfila 2 Hours Before Chatzos
  43. Sof Zman Tfila 2 Hours Before Fixed Local Chatzos
  44. Chatzos
  45. Fixed Local Chatzos
  46. Mincha Gedola GRA
  47. Mincha Gedola 72
  48. Mincha Gedola 16.1º
  49. Mincha Ketana GRA
  50. Mincha Ketana 16.1º
  51. Mincha Ketana 72
  52. Plag GRA
  53. Plag 60
  54. Plag 72
  55. Plag 72 Zmanis
  56. Plag 90
  57. Plag 90 Zmanis
  58. Plag 96
  59. Plag 96 Zmanis
  60. Plag 120
  61. Plag 120 Zmanis
  62. Plag 16.1º
  63. Plag 18º
  64. Plag 19.8º
  65. Plag 26º
  66. Plag Alos to Sunset
  67. Plag Alos to Tzais Geonim
  68. Candle Lighting
  69. Sunset
  70. Bain Hashmashos Rabainu Tam 13.5 Minutes Before Tzais 7.083
  71. Bain Hashmashos Rabainu Tam 58.5 Minutes
  72. Bain Hashmashos Rabainu Tam 13º
  73. Bain Hashmashos Rabainu Tam 2 Stars
  74. Tzais Geonim 5.95º
  75. Tzais Geonim 7.083º
  76. Tzais Geonim 8.5º
  77. Tzais 72
  78. Tzais 72 Zmanis
  79. Tzais 16.1º
  80. Tzais 18º
  81. Tzais 90
  82. Tzais 90 Zmanis
  83. Tzais 18º
  84. Tzais 19.8º
  85. Tzais 96
  86. Tzais 96 Zmanis
  87. Tzais 26º
  88. Tzais 120
  89. Tzais 120 Zmanis
  90. Shaah Zmanis GRA
  91. Shaah Zmanis 72 Minutes
  92. Shaah Zmanis 72 Minutes Zmanis
  93. Shaah Zmanis 16.1º
  94. Shaah Zmanis 90 Minutes
  95. Shaah Zmanis 90 Minutes Zmanis
  96. Shaah Zmanis 18º
  97. Shaah Zmanis 19.8º
  98. Shaah Zmanis 96 Minutes
  99. Shaah Zmanis 96 Zmanis
  100. Shaah Zmanis 26º
  101. Shaah Zmanis 120 Minutes
  102. Shaah Zmanis 120 Zmanis
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2 Responses to “Zmanim Project”

  1. on May 2, 2008 - כ"ח ניסן תשס"ח at 7:07 am 1.Shmuel Weisberg said …

    Shalom,

    I am curious if you’re aware of or compared your calculations to those used in kaluach. (www.kaluach.org). Yisroel also publishes some APIs via his site.

    I am not asking out of idle curiosity but have an interest in knowing whether there are differences. I am not sure what offsets he uses for refraction nor which sunrise sunset calculation he uses. I know that he currently uses 0 elevation.

    Shabbat Shalom,
    (Rabbi) Shmuel Weisberg

  2. on May 2, 2008 - כ"ח ניסן תשס"ח at 11:24 am 2.KosherJava said …

    Rabbi Weisberg,
    I just took a look at the Kaluach JavaScript code (the Windows API is in a DLL/COM object without the sourcecode available to me). From the Javascript source it is clear that the code is based on the USNO algorithm. The offset to the 90° below the zenith used by their code for sunrise/set uses a combined 50′ (minutes of a degree = 50/60 or .83333) for refraction and solar radius. This is pretty much the standard used, where the solar radius is 16′ and the refraction average is 34′. They use the following offsets for zmanim.

    Alos: 106°
    Misheyakir: 101°
    Tzais: 96°

    Please let me know if you have any additional questions, though you are probably better off asking them.

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