And always another good indicator is this. A comparison of King James to Young's Literal.
The "King James" says it is the "first day of the week." "Young's literal" says it is the "first of the week"....both correct, but "first" is more descriptive of the first day beginning at sundown and Paul continuing to preach until midnight.
Many lights being on would indicate an evening, after Sabbath fellowship meal, as they are breaking bread and listening to Paul speak..... until midnight. We also know that the upper room had windows to allow light to enter (if there had been any) because a young man went to sleep and fell out one. (Now we know why the Holy Spirit inspired Luke to tell us the lights were on!)
As a young man, my Grandparents (both sets from the old country) inviting someone over for dinner would say, "Come and Break Bread with Us."
Excellent post, Douglas!
But it was still the "first day of the week", not the last, according to Jewish reckoning. The last day was from sundown Friday to sundown Saturday.
This contrivance only indicates how desperate the last day sabbatarians have become.