You can find an explanation of the meaning of the hours "da campanile" i.e. "a half hour after" in : https://www.academia.edu/2021256/Le_ore_italiane._Origine_e_declino_di_uno_dei_piu_importanti_sistemi_orari_del_passato_seconda_parte_
Regards, Gian Il giorno mer 1 lug 2020 alle ore 17:04 Ross Sinclair Caldwell < [email protected]> ha scritto: > To find some authority for the understanding that the Italian hours begin > at the end of dusk, or about half an hour after sunset, I note that in the > BBS Sundial Glossary under “hour plane” - “Italian” it says - > > > “there is some evidence in older works that Italian hours were counted > from 30 minutes after sunset.” > > http://sundialsoc.org.uk/discussions/glossary-a-z/8/ > > > Does anyone know what this evidence in older works is? > > > A few other places I've looked - > > > Wikipedia says “end of dusk, i.e. half an hour after sunset.” > > https://en.wikipedia.org/wiki/Hour > > > This looked promising - Mario Arnaldi, *Le ore italiane. Origine e > declino di uno dei più importanti sistemi orari del passato (prima parte)* > . > > > https://www.academia.edu/2021250/Le_ore_italiane._Origine_e_declino_di_uno_dei_piu_importanti_sistemi_orari_del_passato_prima_parte_ > > > But he does not mention the notion of "a half hour after" (*mezz'ora dopo*) > sunset (*tramonto del sole*). > > > Ross Caldwell > 43.349399 3.22422981 > Béziers, France > > > ------------------------------ > *De :* sundial <[email protected]> de la part de Ross Sinclair > Caldwell <[email protected]> > *Envoyé :* mercredi 1 juillet 2020 16:41 > *À :* John Davis <[email protected]>; Schechner, Sara < > [email protected]> > *Cc :* 'sundial list sundials' <[email protected]> > *Objet :* RE: Time problem > > Hi John, Sara et al., > > My understanding is that a seasonal (or unequal) hour is a period of time > ('in the first hour' etc) and not an instant. It is never divided up into > minutes and so the time of 6 minutes after dawn must be referring to a time > in equal hours, most probably measured with an astrolabe as you suggest. > > I agree. All that remains unknowable is the visibilty at the time. If it > were overcast at dawn, they must have calculated rather than observed. But > I tend to think it was observed, and determined with an astrolabe. > > Ross > ------------------------------ > *De :* John Davis <[email protected]> > *Envoyé :* mercredi 1 juillet 2020 10:10 > *À :* Ross Sinclair Caldwell <[email protected]>; Schechner, Sara < > [email protected]> > *Cc :* 'sundial list sundials' <[email protected]> > *Objet :* RE: Time problem > > Hi Sara, Ross et al, > > > My understanding is that a seasonal (or unequal) hour is a period of time > ('in the first hour' etc) and not an instant. It is never divided up into > minutes and so the time of 6 minutes after dawn must be referring to a time > in equal hours, most probably measured with an astrolabe as you suggest. > > > Regards, > > > John > > ----------------------- > > > > ------ Original Message ------ > From: "Schechner, Sara" <[email protected]> > To: "Ross Sinclair Caldwell" <[email protected]> > Cc: "'sundial list sundials'" <[email protected]> > Sent: Tuesday, 30 Jun, 20 At 21:20 > Subject: RE: Time problem > > >>> In short, I am researching the biography of Filippo Maria Visconti > (1392-1447), duke of Milan, and you probably know that these Italian > princes relied heavily on astrology. So, Visconti's time of birth is known > precisely - "six minutes after sunrise," Monday, 23 September, 1392. His > natal chart was of course produced and interpreted, but it has been lost. I > am trying to recreate it as it might have been done by a court astrologer > of the time.<<< > > I have some thoughts about ascertaining the time of “6 minutes after > sunrise” in 1392 in Milan. > > First of all, Milan is one of the earliest towns to have a public tower > clock in the 14th century, but it would only strike and show hours > according to local solar time. It would not be divided into minutes. It was > not reliable enough for such a horological chart. > > Sundials would be the more commonly used timepiece, but the six-minutes is > an unusual amount of precision. My guess is that the court astronomer was > using an astrolabe, which can be divided into units in the range of 4-6 > minutes. Many also had arcs for the astrological houses and for both equal > and unequal hours. The actual time might have been taken from a bright star > still visible in the dawn. > > It is also worth considering what this 6-minutes after dawn really means. > Is the astrologer using unequal hours which were still more common in these > early days of clocks? If so, then six minutes would be equal to 1/10 of the > first hour on that day of the year—i.e., 1/10 of 1/12 of the length of > daylight. > > Lastly, in reconstructing a horoscope, one needs to know the position of > the planets to place them on the chart. Some might be observed, but mostly > they are taken from a table. These varied in different manuscript > traditions. Do we have a clue what table the astrologer was using? > > Good luck with your project. > > Sara > > *Sara J. Schechner, Ph.D. * > > David P. Wheatland Curator of the Collection of Historical Scientific > Instruments > > Lecturer on the History of Science > > Department of the History of Science, Harvard University > > Science Center 251c, 1 Oxford Street, Cambridge, MA 02138 > > Tel: 617-496-9542 | Fax: 617-495-3344 > > [email protected] | @SaraSchechner > > http://scholar.harvard.edu/saraschechner > > http://chsi.harvard.edu/ > > ------------------------------ > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > > Dr J Davis > Flowton Dials http://www.flowton-dials.co.uk/ > BSS Editor http://sundialsoc.org.uk/publications/the-bss-bulletin/ > <http://www.sundialsoc.org.uk/bulletin.php> > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > >
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