Classicly

It was customary for terrestrials to use terrestrial dates wherever their outposts were located in the stellar system. But instead of using the terrestrial year—as shown in parenthesis on The Sirian Daily Universe—the year always was reckoned from the date when the planet was first visited by an expedition from the solar system.

Although days were not always the same, twenty-four hour periods could be reckoned quite easily so that on some planets a single day might have more than one terrestrial date, and on others a single day would be a fraction of a legal day. The number of actual days usually was indicated by a Roman numeral preceding the Arabic figure. Thus August V2 indicated that Sirius had risen and set five times while the sun had done so twice during the month of August.