No new sensor this week, no new page. Just a long list of small corrections, none of which would have earned a log entry on its own. Put together, they show what this station spends most of its time doing: looking hard at its own numbers.
It started with the photos. The system that picks the best shot of each pass was quietly unfair to small aircraft, marking down perfect frames because the plane only filled a corner of the sky. It now judges sharpness on the aircraft itself, and night shots against the real time of sunset.
Then the Data page, where an hourly average turned out not to be a true average. Fixed, with clearer labels on what each average actually means.
Then the big one: who flies what. Out of more than 48,000 recorded flights, 846 had no airline attached. By the end of the week, 325. Along the way: a Lisbon charter airline that a public registry had filed under a Canadian company. The Portuguese Air Force's maritime patrols, flying under the callsign OCEAN. Aircraft too new for any registry, like KLM's first A321neo over the terrace on 23 July, and an Iberia A321XLR, the version that crosses the Atlantic with a single aisle, spotted as early as 8 May. And the INEM medical helicopters, which cross our sky on their way to hospital but never through the camera's field of view. They are now recognised with a deliberately cautious rule, and they no longer rank as "the quietest airline of the month", a flattering mistake for a helicopter.
A spotter from Porto, Carlos Miguel Seabra, kindly let us use his photo of one of them. Obrigado, Carlos.
Every correction now has a date and a line in the Archive's Data Quality tab, so anyone can see what changed and why. Researchers get something too: the continuous noise and vibration logs now come in 10-day files, small enough to open in any spreadsheet.
An instrument isn't finished when it starts measuring. It's finished when every number it gives deserves to be trusted, and that, it turns out, is never quite done.