Annual data acquisition yield obtained with our airglow spectrometer (updated until December 31, 2024). From 1984 to late 1997, campaign style operation limited amount of nights to campaign duration. Automatic operation then boosted data acquisition efficiency considerably (also due to improvements of software and hardware, continuous support by observatory staff, and also a certain dose of good luck). The data gap in 2003/5 is due to refurbishment and hardware upgrade.