Eigen Times prints each day's news as coordinates in the eigenbasis of everything that has happened before. Every story is measured against the archive: which archetype it instantiates, how much of it the archive explains, and what is different this time.
The archive holds 16.5 million articles: The New York Times from September 1851 to the present (headlines and abstracts, via the Archive API), The Guardian (1999→), Wikipedia's Current events portal (2002→) and Wikinews (2004–2026). Every article is embedded once with a pinned model and clustered into a day's stories by one procedure, so the backfill and the live stream are measured the same way.
The v1 basis was fitted on the modern corpus (1999–2026). The v2 · 175 years basis is fitted on the whole archive with day-balanced weights: every calendar day since 1851 counts the same, so the axes are the recurring shapes of news across 175 years rather than of the last quarter-century. Each page carries a switch in the masthead; the same day in the other basis is one click away, and the current edition is highlighted.
Two books from First Pair Press describe the system: the paper Eigen Times: A Newspaper in the Eigenbasis of the News (design, dataset, the two algorithms, evaluation and engineering) and its illustrated companion The Mathematics of Eigen Times (matrices, decompositions, thresholds and the streaming computation, with pictures). The design document DESIGN.md in the repository sets out the mathematics in brief.