Dear Andrew (and Fer), Many thanks for this reference...
http://www.aandc.org/research/nautical_time_and_date.html That is a splendid article and shows just what pitfalls one can fall into when attempting to force historical data to fit the present way of thinking! I share your thought... I can't really imagine that even sailors (or astronomers) would have had the day changing name at midday... That said, I have a feeling that when Italian Hours were in common use in Italy both the date and the day name changed at sunset. This is a cue for Italian readers of the list to say that this has been widely discussed before (which is true) and that no widespread agreement has been established :-) One hang-over which still persists in astronomy is the Julian Day Number which changes at noon UTC. As I write, it is Thursday and the JDN is 2455581. In just over four hours time it will still be Thursday but the JDN will be 2455582. The scope for confusion is almost endless. This splendid list has now provided us with pictures of one French Revolution Hours sundial with noon shown as 10 and another with noon shown as 5. Maybe Napoleon didn't write a rigorous spec? Frank --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
