Observerhours

Observerhours is a measure used in scientific observing and fieldwork to quantify the time that observers actively contribute to data collection. Defined as one hour of active observing by a single observer, observerhours can be accumulated across multiple people and sessions. For example, two observers each conducting observations for three hours contribute six observerhours.

Calculation and conventions vary by project, but common practice is to tally the duration of each observing period and multiply by the number of observers present during that period, then sum across all periods. Some programs include instrument setup, target acquisition, and calibration within observerhours, while others count only the time when data are being recorded. Similarly, some conventions treat simultaneous observations by multiple observers as separate observerhours, while others normalize for collaborative sessions.

Observerhours are distinct from telescope or on-sky time. On-sky time typically measures the actual use of the instrument to collect data, whereas observerhours focus on the labor input of the observers. Downtime, weather interruptions, or periods when observers are present but the instrument is not recording data can be counted differently depending on the protocol, which can affect total observerhours reported.

Applications of observerhours include project planning, manpower budgeting, and grant reporting. Reporting through observerhours provides a transparent way to convey the scale of human effort behind data collection, complementing technical metrics such as total observing time and data yield.

See also: observing run, telescope time, man-hours, data collection.