We only count nights, when there are at least 40 data sets. These normally comprise OH and O₂ temperatures and intensities, but emphasis is on temperatures, because cloud absorption may decrease the amount of intensities, often leaving temperatures unaffected.

As can be seen by clicking on any year in the "data set" table, nocturnal data acquisition throughout a year is only rarely that poor - except when observing conditions or instrument problems directly impede any data taking.

The average data acquisition yield in successful nights, so defined, is about 300.