Chromaticity dependence on octupole strength

The first measurements of the dependence of the chromaticity on the lattice octupole strength were performed at the LHC in a machine development session on Wednesday 20 June 2012. This chromaticity change is non negligible and needs to be taken into account when changing the octupole strength, e.g. for beam stabilization purposes. We report on the results of such measurements and later ones, along with some predictions and some first estimates of systematic horizontal and vertical misalignments of the octupoles