August 7, 2008

First Century Calendars

About 2 or 3 years ago I made calendars (like the ones here and here) showing the Jewish Holidays over the Roman Calendar. I've got print outs from 9 BC to 70 AD that I'd like to scan and post online, but it's a lot of busy work. If anyone wants to help, let me know. Or can anyone tell me how to make a one page Word Doc directly into a jif or jpeg image? (As of now, all I know how to do is print and scan. Thus, the long postponed busy work.) However we do it, and whoever has the time and desire to get this done, we can post them jointly. Let me know...

Again, I have 79 Calendars ready for web publication. Got time to help get that done?


Academic Full Disclosure: The source for my calendars were the websites www.hebcal.com and www.timeanddate.com. Hebcal used fake-Gregorian dates, easily convertible for the years 1 to 70 AD. (Hebcal also doesn't go into "BC" years, which seems odd for them.) I also double checked my pages against the impressive interface at www.abdicate.net/cal.aspx. (No idea what the rest of that site is about; I haven't read it.) These are the only three sources I used to make my calendars. Hebcal and Timeanddate seemed extremely reputable and you can find more info on those sites on the methods/sources for their calculations.

Here is what I can tell you about how I put the sites' info together: Timeanddate gives the dates of lunar phases straight up, which of course correspond to the Festival dates shown by Hebcal. Hebcal had the holidays on the proper day of the week, but the Roman date was "off by two" because their computer program used the Gregorian formula. Yes, the Julian Calendar was off by more than two when Gregory revised it in the 1500's. But it took a while to get so badly off. The only reason the program is off by two is because it retroacts Gregory's revision which, after enough centuries of going backwards, results in an increasing "over-correction". But again, these concerns only affect our understanding of computer programs such as the one used by Hebcal. Incidentally, Timeanddate (and the abdicate site) will give you Julian OR Fake-Gregorian dates for the first century so you can verify what I'm talking about here.

As a side note - I have (over the years) noticed some discrepancy in uncited references to Kepler's dates for the 7 BC triple-conjunction of Jupiter with Saturn. I wonder what sources they were using. But I can't say too much yet - it's still on my way-back list (in order to double check what I put in the Year Book for 7 BC) to somehow find a real scholarly citation by actual astronomers for those dates. At any rate, the Star of Bethlehem is a whole other issue. Completely aside from that, I believe the calendars I want to post online are solid.

Again, who wants to help get that done?

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