J.Jean Ajdler has an MS in engineering and works as a civil and structural engineer.
He writes about medieval Jewish astronomy, the history of the Jewish calendar , and the Talmudic metrology.
He is the author of the book: Hilkhot Kiddush ha-Hodesh al-pi ha-Ramban, Sifriati 1996, and has published in Tradition (New- York), BDD ( Bar-Ilan), Hakirah (Flatbush) and Tsohar (Rabbanei Tsohar).
1. J.J. Ajdler, Rav Safra and the second festival Day: Lessons About the Evolution of the Jewish Calendar , Tradition, Vol 38 nr 4, 2004, pp. 3-28.
2. J.J. Ajdler, The equation of time in Ancient Jewish Astronomy, B.D.D. nr 16, August 2005, pp. 5-56.
3. J.J. Ajdler, Talmudic Metrology I. The Mile as a Unit of Length , B.D.D. nr 19, January 2008, pp. 55-83.
4. J.J. Ajdler, Talmudic Metrology II. The Mile as a Measure of Time, B.D.D. nr 20, May 2008, pp. 6-37.
5. J.J. Ajdler, The Order of Lighting the Hanukah Candles: The Evolution of a Custom and the Influence of the Publication of the Shulhan Arukh , Hakirah Volume 7, 2009, pp. 205-227.
6. J.J. Ajdler,Talmudic Metrology III. Units of Measure of Volume and Capacity, B.D.D. nr 21, March 2009, pp. 7-59.
7. J.J. Ajdler, The Jewish Calendar: Past and Future , an extract of the paper has been accepted for publication in B. D. D.
8. J.J. Ajdler, Luhot ha-Ibbur, part 1. B.D.D. 29, December 2014, pp. 15-54.
9. J.J. Ajdler, Luhot ha-Ibbur, part 2. B.D.D. 30.
10. J.J. Ajdler, The Equation of Time in Ancient Astronomy.
11. J.J. Ajdler, Rabbi and his Lineage.
12. J.J. Ajdler, The Day and its Hours in Ancient Jewish Astronomy. Accepted for publication in B.D.D
13. J.J. Ajdler, A Short History of the Jewish Calendar.
14. J.J. Ajdler, Talmudic Metrology IV: Halakhic Currency. B.D.D. nr 22, December 2009, p.p. 7-50
15. J.J. Ajdler, Talmudic Metrology V: Halakhic Coinage in Post-Talmudic Period. B.D.D. nr 23 July 2010, pp. 7-28.
16. J.J. Ajdler, Talmudic Metrology VI: Sabbath's Limits and the Jewish Time Reckoning. B.D.D nr 24, March 2011, pp. 7-66.
17. J.J. Ajdler, Talmudic Metrology VII: Sabbath's Limits and the Jewish Time Reckoning (Following). B.D.D. 26, April 2012, pp. 21-63.
18. J.J. Ajdler, Talmudic Metrology VIII: Hours and time reckoning in the Talmudic and Rabbinic Literature. Accepted for Publication in B.D.D. 31, November 2016, pp. 7 - 39
19. J.J. Ajdler, Stability Problems in the Tabernacle Accepted for publication in B.D.D.
20. J.J. Ajdler, The Gregorian revolution of the Jewish Calendar. B.D.D. nr 27, March 2013, pp. 17-76.
21. J.J. Ajdler, The Period of 689,472 years in the Jewish Calendar and its Applications in Frequency and Probability Problems. B.D.D. 28, December 2013, pp. 5-44.
22. J.J. Ajdler, The Future of the Jewish Calendar. B.D.D. 25, September 2011, pp. 7-43.
23. J.J. Ajdler, Early and Late New Moon's sightings in the Jewish Calendar. Accepted for Publication in B.D.D.
24. J.J. Ajdler, Yom Tov Sheni Shel Galuyyot. The True signification of the Second Festival Day. Accepted for Publication in B.D.D.
25. J.J. Ajdler, Yom Tov Sheni Shel Galuyyot and the Minhagim with Regard to the Travelers. Published on Feedbiz: the seforim Blog, Tuesday, June 07, 2011.
26. J.J. Ajdler, Rosh ha-Shanah in Palestine at the time of the Inception of the Jewish Calendar: One or Two days? Accepted for Publication in B.D.D.
27. J.J. Ajdler, The Beginning of the Jewish Calendar: Addenda and Corrigenda. Letter to the Editor in Hakirah, Volume 9, Winter 2010 pp. 9-12.
28. J.J. Ajdler, Answer to the Letter to the Editor of Prof. Marc B. Shapiro. Hakirah, Volume 8, Summer 2009, pp. 16-17.
29. J.J. Ajdler, The Shape of the Menorah, Daniel Michelson. Letter to the editor in B.D.D. nr 24, March 2011, pp. 85-87.
30. Sefer Hokhmat ha-Tekhunah, R. Raphael Levi from Hanover. Edited from a manuscript in the Bodleian Library in Oxford. Edited and Commented by ir. J. J. Ajdler.
31. Sefer Tekhunat ha-Shamayim (ha-Arokh), R. Raphael Levi from Hanover. Edited from a unique and autographic manuscript in the Bodleian Library in Oxford. Edited and Commented by ir. J. J. Ajdler.
32. Sefer Klalei Sod ha-Ibbur ve ha-tekhunah, R. Raphael Levi from Hanover. Edited from a Unique Manuscript in the Bodleian Library in Oxford. Edited and Commented by ir. J. J. Ajdler.
33. J.J. Ajdler, About Hanover's fundamental rule of the Jewish calendar.
34. J.J. Ajdler, Book Review: Virtual edition of three new books of Raphael Levi Hanover still in manuscript. B.D.D. 27, March 2013, pp. 77-91.
35. J.J. Ajdler, Methodologies Used by Poskim to Determine Orientation of Synagogue. Addenda et Corrigenda. letter to the Editor of Hakira.
36. J.J. Ajdler, The Orientation of the Synagogue: the Direction of the Prayer. Accepted for Publication in B.D.D.
37. J.J. Ajdler, Peirush al Hilkhot Kiddush ha-Hodesh: Joseph Solomon Delmedigo.
38. J.J. Ajdler, The Addition of a Leap Second to the Coordinated Universal Time and its Impact on the Determination of the Molad. Prof. Ariel Cohen. Letter to the Editor, B.D.D. 26, April 2012, pp. 65-68.
39. J.J. Ajdler, How Maimonides chose his epoch. Clarifications regarding the astronomical calculations in the Sanctification of the new moon. Prof. Ariel Cohen. Letter to the editor, B.D.D. 27, March 2013, pp. 93-100.
40. J.J. Ajdler, Preventing Get Refusal According to Halakah.
41. J.J. Ajdler, The strange destiny of a responsum of Rashba.
42. J.J. Ajdler, . פתרון הלכתי לבעיית סרבנות גט
43. J.J. Ajdler, A complete solution to the Agunah Problem: is it a utopian project? Addenda and Corrigenda to the Broyde tripartite agreement: a solution without any innovation.
44. J.J. Ajdler and I. Eichenstein, Between Ptolemy and al-Battani: Elements of the astronomy of Rabbi Abraham bar Hiyya ha-Nassi, according to his book Sefer Mehalekhot ha-Kokhavim.
45. J.J. Ajdler, The Precession of the Equinox in the Ancient Jewish Astronomy.
46. J.J. Ajdler, A Historical Outline of the Understanding of Maimonides? Astronomical Chapters of Hilkhot Kiddush ha-Hodesh. Examination of two Neglected Pieces of Evidence.
47. J.J. Ajdler, Maimonides in the Guide of the Perplexed I: 73, בנושא הקווים שני, on the Proposition II:14 in Apollonius?Second Book of the Conic Sections.
48. J.J. Ajdler, Book Review: Haym Soloveitchik. Collected Essays II. The Littman Library of Jewish Civilization 2014.
49. J.J. Ajdler, Rashba and Maharam: The Relation between Rashba and Maharam of Rothenburg. Rashba and Capital Punishment of Informers.
50. J.J. Ajdler, Pidion ha-Ben: an obligation on the father or the son?
51. J.J. Ajdler, Hebrew. Does a freely accepted penalty invalidate the Get? Tsohar 39.
52. J.J. Ajdler, Hebrew. Answer to rejoinders. Tsohar 40.
53. J.J. Ajdler, Hebrew. Rejoinder to three papers published in Tehumin 34 and 35.
54. J.J. Ajdler, Hebrew. Rejoinder to the paper of R. Pinhas Shapira published in Tehumin 35.
55. J.J. Ajdler, Hebrew. About Hanover's fundamental rule of the Jewish calendar
56. J.J. Ajdler, English. Mitsvat asse she ha-zeman gerama
57. J.J. Ajdler, En Francais. Le get et le divorce religieux. La Tribune Juive 28/05/2014.
58. J.J. Ajdler, A reaction to Eran Raviv's articles published in B.D.D. nr. 22, 26, 27 and 28 versus my paper published in B.D.D. nr. 28.
59. J.J. Ajdler, How did Maimonides choose his epoch? Explanations about the astronomical calculations in H.K.H.
60. J.J. Ajdler, The German tradition of the Shekel.
61. J.J. Ajdler, Les Hasards du calendrier juif.
62. J.J. Ajdler, The hazards of the Jewish calendar.
63. J.J. Ajdler, Luhot ha-Ibbur II, BDD nr 30 pp. 7 - 48. Additional considerations about the Molad and the mean conjunction.
64. J.J. Ajdler, The Jewish calendar during the Talmudic period.
65. J.J. Ajdler, Do questionable stringencies endanger prenuptial agreements?
66. J.J. Ajdler, A few words about the sidra and Yossef.
67. J.J. Ajdler, About seoudat Mitsvah and Bat Mitsvah.
68. J.J. Ajdler, Mattot-Masseh: devar Torah.
69. J.J. Ajdler, The story of Yossef. Why did Yossef not contact his father during 22 years?
70. J.J. Ajdler, Bat Mitsvah dracha about sidra Ba'alotkha.