benyaming
commented
3 years ago - all chabad zmanim: https://www.chabad.org/library/article_cdo/aid/3209349/jewish/About-Our-Zmanim-Calculations.htm
- kosher java implamantation: https://kosherjava.com/zmanim/docs/api/index.html
- discussion in telegram under this post (ru): https://t.me/zmanim_bot_log/43