You may have heard that the Islamic Day ends at Maghrib (sunset) time. Imagine a society which actually lived this rather than it being an interesting fact.

The Ottoman Turks commence their reckoning of time from sunset. This is with them the twelfth hour, an hour later it is one o’clock, and so on till the twelfth hour in the morning (6 a. m.), when they begin again. This is called alatourqa (Turkish), to distinguish it from European time, which is called alafranqa (French, European).

ref:
Ottoman-Turkish Conversation-grammar: A Practical Method of Learning the Ottoman-Turkish Language
By V. H. Hagopian
Published by Groos, 1907

Speaking about Ottoman Time, below is an excerpt of an interesting article about Ottoman timepieces:

One, by the Arab scientist al-Jazari, called the “Book of Knowledge of Mechanical Contrivances,” also known as the “Treatise on Automata,” furnished detailed drawings of over 50 mechanical devices, including clocks. The other, by the astronomer Taqi al-Din Muhammad ibn Ma’ruf, published in Istanbul, described the mechanics of astrolabes and observational telescopes as well as weight-driven clocks. These indicated hours and minutes and could determine the time of prayer “without having to observe the heavenly bodies,” that is, when indoors or on overcast days.

The detail provided by al-Jazari and Taqi al-Din amounted to a “how-to-do-it” manual for the Ottoman clockmakers, who seem to have been the first among Muslims to actually go ahead and construct an elaborate mechanical timepiece.

As in medieval Europe, where the first geared clocks are believed to have appeared in monasteries to help regulate the daily prayer services, so in Istanbul the first Turkish clocks were made in the tekkes, or monasteries, of the so-called “Turkish monks,” the Mevlevi Dervishes, better known to Westerners as the “Whirling Dervishes.” The Mevlevis were considered the most intellectual of the Dervish orders and were well known for their interest in music and the arts. They acquired an interest in making mechanical clocks, their elders now suggest, to help initiates of the order observe fixed prayer times during long periods of meditation. More reliable than sundials and not requiring as much attention as a waterclock, the clocks also provided a focus for the communal life of the monastery.

As artisans, the Mevlevis prided themselves on producing flutes, embossed swords and other objets d’art. Clock-making required a combination of talents. The purely mechanical aspect drew upon the genius of scholars like Taqi al-Din, who had studied Arabic and Persian scientific writings, while making the outer encasement required the coordinated skills of metalworkers, cabinet makers and jewelers. Available manuscripts say very little about the actual method of manufacture, but it is apparent that the Mevlevis spent several years on each timepiece, with only the most basic of hand tools. Occasionally, the same artist would make the entire apparatus, from the inner gearwork to the intricately embellished case.

The outer design frequently took the shape of the Mevlevi headdress. This consisted of a felt hat like a tall, overturned plant pot, encircled at the base with a turban; it served as a symbol of the order and usually appeared as a sign on top of the tekke or on the Dervishes’ gravestones.

An extraordinary example of encrusted jewel work and embellishment is the round wall clock signed by Shahiz, made about 1650. Covered with filigree work with inlaid rubies, emeralds and diamonds, the face is in the form of a wreath in blue enamel with white numbers, and the back—which, of course, was rarely seen—is also richly engraved with leaves and fleurons. A pocket watch, made by Meshur Sheyh Dede in 1702, shows, as well as hours and minutes, Gregorian and Arabic calendars and the signs of the Zodiac.

A clock made by Mehmet Sükrü in 1853, thought to be the only one of its kind, has a double escapement mechanism which permits it to operate unaffected by extremes in temperature. Another, made by Ahmed Dede about 1865, has a combination escapement and pendulum mechanism which is also insensitive to variations in temperature and is accurate to less than one second per 24 hours.

Many of these timepieces, now on display at the Topkapı Palace, were presented to the Sultan by the Mevlevis as a sign of their loyalty. A 16th-century illuminated manuscript shows a procession of different artisans before Sultan Murad III, and an account of their visit in a royal diary mentions among those who presented themselves to the Sultan the “magic” Mevlevi clockmakers. As the assembled audience watched in amazement, the diary tells us, they entered the hall with an oversize model of a clock gearwork mounted on a wagon. A hammer automatically struck the gearwheel, turning a second wheel which, the chronicler observes, “could perform the work of a dozen persons.” The Sultan and his audience burst into applause and cheered the clockmakers as they pulled their display away.

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The small number of Turkish clocks in the Topkapı Palace collection doesn’t indicate, as might be assumed, that European competition eventually forced the Turkish clockmakers out of business. In fact the Turkish clocks were, from the beginning, a labor of love by scholar-craftsmen motivated by religion, their interest in art and devotion to the Sultan. They were never concerned with profits or large-scale production. In fact, before the Republican regime banned all Dervish orders in 1923, the Mevlevis probably actually made few more than the some 30 timepieces known to have survived in the Sultan’s palaces and in the houses of their order, a uniquely Turkish contribution to Muslim craftsmanship.

ref: “Saudi Aramco World: Topkapi’s Turkish Timepieces – James Horgen