This is a calendar from the Karaite-Korner. The Karaites are a sect of Judaism who reject man-made additions to the word of the Lord. So their calendar is based purely on the Bible. They are very cool people so I recommend checking out their website. They do localize it to Israel, and personally I’m of the opinion it should be localized to whatever locale you are in if possible. So I look for New Moons locally and this can affect the date of holidays in the continental United States.