I am sure we both understand Mark 15:42 insofar as what the passage actually teaches.
You presented a theory and asked for others to challenge it. I did.
You do not understand the passage insofar as what it isn't teaching. You also do not appear to know your history.
The Jews stopped using the Biblical calendar (the lunisolar calendar by observation/ messenger). One reason give was opposition that made observation difficult. Another was the exile.
The Bablyonian Disporia based their dating on year of "the captivity of Jehoiachin".
During the Hasmonean period the Jews adopted the Seleucid era counting.
Until the 10th century they used the "Era of Contracts:.
Then you had the anno mundi system.
In the 12th century AD the Jews adopted a mathematical lunisolar calendar (the one you keep posting) to strictly follow the Law. It does what observation couldn't.
In the end it does not matter. You are wrong because, as @Alan Gross noted, Mark woukd have reported what did happen in the first century- NOT what should have been done following a more percise 12th century calendar.
We can't know the year because we do not have the calendar used (which was dependent on the Sanhedrin). BUT we do know the days the 1st century Jews observed because these were recorded.
You have convinced yourself of an impossible date for the crucifixion. The funny thing is we can't know the exact date (which is why you rely on a modern calender), but we can know by Scripture that your date does not work. You simply can't see it because you are determined to dogmaticlly know what you cannot.
