“For your information, this is a subject that I have been interested in for many years, and what I am telling you here is not “google ben yomo”, but things that I have known for a long time.”
I dont get the google ben yomo reference.
I too have been interested in this for many years. Although unlike you I have done more through research. (you freely admit you arent familiar with a work on this very topic) I dont know you I am familar with him and his work.
If you are interested in time related cocepts in general as they relate to halacha. I I highly reccomend his sefer it is called Shaarei zemanim. You may learn something
Your discussion “As a concrete example, let’s say that half the molad period is exactly 1275722 seconds…” is anachronistic. (though admittedly the idea of subtracting 27 seconds is anachronistic too, though you earlier didnt like my rounding 20 minutes 56.5 sec to 21 minutes which is of course less of a difference than 27 seconds) Chazal’s times were not that precise. Nonetheless Any “correction” made is ignored.
For example. While Tekufas Rav Ada is more accurate than That of Shmuel. It is still less accurate than what we know today, we still go with it although we can see Yomim Tovim sliding forward through the seasons.
See Irv Bromberg’s website where he suggests various fixes too the calendar to correct for drift.
Nonetheless even you accept his fixes. They wouldn’t change the halacha.
The Julian calendar that we use for Vesein Tal and Birchas hachama is visibly off. As you may know while a more accurate one is avaliable we dont correct our calcualtion. We stick to chazal’s (although it isnt as precise)
Another attempt
In the back of R’ Dovid Feinsteins’s book on the calendar there are instructions to construct an excell spreadsheet with molados for 247 years
The molad for Cheshvan 5928 will occur Tue Oct 13 2167 6:16 PM 0 chelakim
Suppose I want to set a google reminder for the latest time for kiddush levana.
So you add 14 days 18 hours 396.5 chalakim
yielding Wed Oct 28 2167 12:38 PM (and 0.5 chelakim)
I will be in E”Y so I subtract the 20 min 56.5 seconds that must be subtracted.
Thus the latest time to say kiddush levana Cheshvan 5928 will be 12:17:03.
Are you saying that isnt true. That there is no way to calculate when kiddush levana will end?
Are you saying that no matter how many seconds, minutes? hours? get added to the calendar over the next 140 years I can jjust check my clock and as long as it says 12:17:02 I still have a second for kiddush levana?