Observations in an Observations Window are logically grouped in observation sets. Observation sets are typically used to make logical partitions in large volumes of observations, e.g., to partition per night or per observer. Peranso offers an extensive set of commands that operate on all observations of an observation set at once (e.g., to average an observation set).

The example below shows 7 observations sets with observations of minor planet 1036 Ganymed, obtained during 7 consecutive nights.

Observations of minor planet 1036 Ganymed obtained by the prolific photometrist 
F. Pilcher (Organ Mesa Observatory, MPC code G50) using a 0.35m f/9.1 SCT.