Counting the hours
There are several ways to count the hours:
In cultures of ancient and medieval world, where more care about the division between day and night than in societies that use artificial lighting, counting the hours began sunrise. Sunrise always fell on the first hour, noon, at the end of the sixth hour and the sun rising in the west end of the twelfth hour. It follows that the length of time varied according to the season. This type of online timer counting is sometimes possible to see the astronomical clock and the astrolabe such as "Babel" clock. It is also used in Jewish religious law (Halacha) and Jewish texts.
The so-called Italian time, or "Italian hours" or "walnut hours," began the first hour of the evening (or at the end of dusk, ie, half an hour after sunset, depending on local practices). So it was probably in connection with the canonical start. Hours are numbered 1 to 24 For example, in Lugano dawn in December fell to 14 noon hour and then at 19 hour; dawn in June fell to 7 hour and noon was 15 hours. Sunset was always located at the end of 24 hours. This counting hours had the advantage that each had an overview of how much time is left to complete the work in time wages in daylight. This method of counting hours was used in Italy in the 14th century until the mid-18th century, even in some parts of the mid-19th century. He was also the 17th century used in Poland and the Czech Republic. In the countries of the Czech crown, then the system was called the Czech hours, but in the last two centuries German was forced out of hours. The system of Italian hours can be seen in many hours in Italy, while the dial is numbered 1 to 24 in Roman or Arabic numerals. Clock movements were adjusted when the beginning of the first hour deviated from sunset least a quarter of an hour. For this purpose, online stopwatch special tables were prepared. A well-known example is the clockwork tower located on St. Mark's Square. Mark in Venice.
The medieval Islamic day began at sunset. The first prayer of the day (maghrib) is performed between sunset and the end of twilight.
In some South German cities such as Nuremberg and Regensburg were used from the late Middle Ages, the great clock (Große Uhr). The day was divided into 24 hours, but counted separately hours day and night hours separately. Bell called garaus then the day began and with it end when. Day and night, so different at different times of the year the number of hours, eg December day was only 8 hours (clock tower and striking through the day 1 to 8), in Jun
For a modern twelve-hour clock mechanism, the clock will start counting at midnight and then again from one noon. Hours are numbered 12, 1, 2, ..., 11 Solar noon is always close at 12 o'clock noon, it differs from it in accordance with the equation of time (around 15 minutes in both directions). At the time of the equinox falls sunrise at 6 AM (Meridiem ante, before noon) and sunset at 6 PM (Post meridiem, after noon). This method of counting penetrated from the first half of the 16th century also to the Czech lands and from 17 century there was the most common means of determining the time of day. Because spread to Central Europe from Germany, in the various countries where it gradually replaced the Italian clocks, called German or German time clock.
In modern machines the clock 24 hours hours commence at midnight and are numbered from 0 to 23. like on http://onlinestopwatchtimer.com. Solar noon is always around 12 hours (again, varies according to the equation of time). At the time of the equinox the sun rises under this count around 06:00 and sets at 18:00.
Sunrise and sunset are much easier to recognize time points day than noon or midnight, start counting the hours from these points was because for most people by far easier than counting the hours since midnight or noon. Nevertheless, with modern astronomical equipment (and the telegraph or similar device capable of transmitting time signals in fractions of seconds) ceased to be a serious problem.
Astrolabes, sundials, and astronomical clocks sometimes show the hour length and count them under the old definitions and counting methods.