Flux Offsets

When combining data from different instruments or observing modes, the datasets may have different absolute flux calibrations. A small mismatch in the flux scale between instruments—even at the fraction of a percent level—can introduce systematic biases in the joint fit if left unaccounted for.

ExoIris handles this through a system of offset groups. One group serves as the reference, and all other groups receive a fitted additive correction. Offset groups are useful whenever you combine datasets from different instruments, spectral orders, or observing programmes.