A stardate is a fictional system of time measurement developed for the television and film seriesStar Trek. In the series, use of this date system is commonly heard at the beginning of a voice-over log entry, such as "Captain's log, stardate 41153.7. Our destination is planet Deneb IV …". While the general idea resembles the Julian date currently used by astronomers, writers and producers have selected numbers using different methods over the years, some more arbitrary than others. This makes it impossible to convert all stardates into equivalent calendar dates, especially since stardates were originally intended to avoid specifying exactly when Star Trek takes place.
Original stardate
The original 1967 Star Trek Guide instructed writers for on how to select stardates for their scripts. Writers could pick any combination of four numbers plus a percentage point, and aim for consistency within a single script, but not necessarily between different scripts. This was to "avoid continually mentioning Star Trek's century" and avoid "arguments about whether this or that would have developed by then". The original series would be officially placed between the years 2265 and 2269, with the second pilot beginning on stardate 1312.4 and the last-produced episode on stardate 5928.5. Though the dating system would be revised for , the pilot of Star Trek: Discovery follows the original series' dating system, starting on stardate 1207.3, which is stated precisely to be Sunday, May 11, 2256.
Revised stardate
The three 1990s Star Trek series followed a new numerical convention. ' revised the stardate system in the 1987 Star Trek: The Next Generation Writer's/Director's Guide, to five digits and one decimal place. According to the guide, the first digit "4" should represent the 24th century, with the second digit representing the television season. The remaining digits can progress unevenly, with the decimal point usually counting days. Stardates of ' began with 46379.1, corresponding to the sixth season of Star Trek: The Next Generation which was also set in the year 2369. ' began with stardate 48315.6, one season after TNG had finished its seventh and final season. As in TNG, the second digit would increase by one every season, while the initial two digits eventually rolled over from 49 to 50, despite the year 2373 still being in the 24th century. ' was set around stardate 56844.9.
Other stardates
Additional Star Trek media have generated their own numbering systems. The 2009 MMORPGStar Trek Online takes place on stardate 86088.58, in the year 2409. Writer Roberto Orci revised the system for the 2009 filmStar Trek so that the first four digits correspond to the year, while the remainder was intended to stand for the day of the year. In the first installment of the movie trilogy, Spock makes his log of the destruction of Vulcan on stardate 2258.42, or February 11, 2258. Star Trek Into Darkness begins on stardate 2259.55, or February 24, 2259. Star Trek Beyond begins on stardate 2263.02, or January 2, 2263.
