This German standard is similar to ISO 3159 that forms the basis for COSC certification. Watches are tested for compliance with DIN 8319 at Glashütte Observatory. The DIN 8319 procedure requires 15 days of testing, in the same positions as for COSC (dial up, dial down, crown left, crown on top, crown below), with an average daily rate variation between -4 and +6 seconds. Average daily rate deviation must not exceed 2 seconds, and largest rate deviation must not exceed 5 seconds. Watches are tested at 23°C, 8°C and 38°C. Watches are wound once every 24 hours. On the tenth day of testing, any complications (typically a chronograph) are activated to ensure that they do not detrimentally affect precision.
Most of these parameters are identical to ISO 3159 and COSC. However, DIN 8319 is more stringent in two ways. Watches must have the stop-second function, and they are tested while completely assembled in their cases.
The Glashütte Observatory Certificate can be issued only to watches that are assembled in Glashütte, and whose movement comprises at least 55% of components made in Glashütte.