The astronomical situation of avishraa is unlike that of worlds such as Earth, which orbit their star directly. It is not a planet, but a natural satellite, a moon that is tidally locked to its parent gas giant Kastun; its closest equivalent of a “month” (the amount of time for Kastun to complete a full cycle of phases) is over 54 Earth days long, and, because it rotates in the same period of time as it revolves around the giant, so is the equivalent of a “day” (the amount of time for the sun to return to its position from the previous day). Meanwhile, its closest equivalent of a “year” (approximately, the amount of time Kastun takes to go around its sun), is generally only of astronomical significance, since due to Avishraa’s minute axial tilt and orbital inclination, annual seasonal variations are sufficiently unremarkable that they are little noticed by its natives.

From this it follows that the measurement of time on Avishraa, at least if it is based around the movement of celestial objects, will be most naturally expressed in units different from those on Earth. Both the takmar and the xtauh have built systems of timekeeping with these considerations in mind.

While many systems of timekeeping exist on Avishraa, the one that is most widespread - and the one used throughout this wiki as the standard of timekeeping - is the Imperial Calendar, part of the vast legacy of the Sixfold Empire that once dominated takmakind. A summary of its workings is below.

The foundation of Imperial timekeeping, and indeed of almost all systems of timekeeping on Avishraa, is what is in this system called the “turn”, which lies at the heart of a system of units based around it, in multiples or divisions of thirty-six. (Since the imperial numbering system is also base-36, this makes it relatively easy for young takmar to learn to tell time.) These are listed below, in order from smallest to largest unit.

(To convert between Earth units and Imperial units, feel free to use this handy converter, courtesy of pinkgothic!)

The breath is one thirty-sixth of a pause, or about 2.816 seconds. Because few takmar have access to clocks, the precise definition is mainly used by scholars, and the term is mainly used to indicate a moment or brief duration of time in general.

The pause is one thirty-sixth of a rest, or roughly 1.69 minutes. Although the precise definition of the pause is more used by scholars than by others, it nonetheless tends to be used somewhat more accurately than the breath, as it is a measure of time capable of being observed in an hourglass or a large sundial.

The rest is one thirty-sixth of a vigil, or almost fifty seconds longer than an hour. Easily observed and measured by the timekeeping equipment available to most takmar. An old-fashioned but persistent way of dividing up the rest is into sixths (each equivalent to six pauses), called walks, of 10.14 minutes or six pauses each; this method of measurement dates back to a period when sundials were usually small and relatively inaccurate, and were limited in their ability to show smaller divisions of time.

The vigil is one thirty-sixth of a turn, or less than three seconds short of 36.5 hours. The vigil was named for the fact that it is roughly as long as an adult takma can go without sleep, unihemispherical or otherwise, without suffering negative consequences, as one might in circumstances requiring lengthy wakefulness. Nonetheless, given the choice, a more reasonable periodicity of unihemispherical sleep is in the region of thirty-two to thirty-four hours for an adult. Prior to the institution of more regularized timekeeping, therefore, a more usual measure of time on this scale was called the sleep, of which there were forty in a single turn and which lasted 32.4 hours.

The turn is one thirty-sixth of a cycle, or less than two minutes short of 54.75 Earth days. This refers to the Avishraan day/month equivalent: Kastun moves through its phases in this amount of time, and the sun completes one full cycle in the sky. Despite its astronomical equivalence, however, the length of a turn and its strong influence on local weather conditions – far stronger, in fact, than that of its astronomical year, which has hardly any – cause it to be treated in importance more suited to an Earthly year, though cycles are a more common long-term measure of time.

The cycle is thirty-six turns, or nearly 1971 Earth days (roughly 5.41 Earth years). The cycle is the most frequently used unit for long-term timekeeping, in the same way that years are used on Earth. As a result, cycles, in combination with turns or other divisions, are the units most often used to measure a takma's age. Relatively few takma cultures count age solely by turns, except in the case of children younger than a cycle or two.

The hexatrigesimal (a more to-the-point translation might be “block-of-36” or “36ade”) is thirty-six cycles, or roughly 194.8 Earth years. Even the very oldest takmar, other than Chosen, have only barely made it to four-sixths of a hexatrigesimal (24 cycles), and only in legends have they reached an entire hexatrigesimal or more; as such, these units are most often used to refer to once-in-a-lifetime or historical events, and are not used as formal calendrical units.

The Imperial calendar does not rely on a single epoch, or starting point, in the way that the AD calendar does, but on a series of them, dividing history into eras. The ultimate beginning of the Empire lying in the establishment of the Sixfold League approximately 267 cycles ago, the first era begins in that cycle (1 Dawn).

Some of the eras recognized today are not those used in the times which fall within those eras. The Imperial government had the prerogative to define when eras started, not merely in the present but retroactively; although during certain periods new eras would be proclaimed for self-serving or frivolous reasons, many cycles later a subsequent government would abolish or combine eras more sensibly. Particularly after the Overturns, proclaiming new eras became regarded as an incredibly solemn and important affair and was rarely done.

When the Empire ended 85 cycles ago, the numerous successor states took their own paths with regard to the era. Many of them, either out of a hope for the Empire's reassembly, or a belief in its rightful authority, or because they simply had bigger things on their mind after the chaos of the fall, simply continued using the last era as if nothing had changed. In the modern day, however, most post-Imperial states recognize at least the end of the Empire as the beginning of a new era. Although in some of them this has already been followed by other eras, the identification of the end of the Empire with the beginning of the present era is wide enough that it is usually understood, if not actually accepted, everywhere.

Before the Sixfold League, and even well into its existence, although turns and vigils were counted in the same way in the League's territories, cycles were counted by reference to the local ruler's reign. For the purpose of putting pre-Imperial history unto a unified framework, scholars have grouped all cycles before 1 Dawn into the Ancient Era, counting backwards from a cycle 0 (the cycle before 1 Dawn).

When writing a date:

• First comes the cycle, which is counted from the first cycle of the era; the number increases at the beginning of each cycle (i.e., when the first cycle is completed, the one following it is immediately labeled 2). The Ancient Era is the exception to this rule only in that the last year of the era is 0 Ancient, with the one before it being 1 Ancient, etc.
• Following the enumeration of the cycle is the name of the era in which the cycle falls; by long convention, a cycle always falls entirely within one era, rather than being split between them. The present era, even if its start is agreed upon as the end of the Empire, is known by different names in different places, but the most common is Cloud.
• Next, the turn is indicated by a numeral.
• The last position can be taken up either by the numeral of the vigil, if this is known (in which case it is separated from the turn by a colon); or, if it is not precisely known (particularly regarding events in the distant past) or that level of accuracy is not considered important, an older convention may be used whereby the turn is divided up between six approximately equal phases, starting at sunrise: Brightening, Radiance, Dimming (ending at sunset), Waxing, Vigilance, Waning.

As an example, the date of an event occurring before sunset during the thirty-fourth turn of twelfth cycle of the Glory Era would be written:

12 Glory 34 Dimming