The Herschel Oxygen Project (HOP) is Herschel Open Time Key Program (KPOT_pgolds01_1). The main goal of HOP was to use HIFI to probe a range of molecular cloud environments to detect molecular oxygen. The three strongest transitions in the range covered by HIFI from energy levels lower than 120 K above the ground state were selected (487.3 GHz, 773.8 GHz and 1120.7 GHz) for the following targets: Sgr A, Sgr B2(S), OMC-1(Peak 1), Orion Bar, rho Oph A, NGC 1333 IRAS 4A, NGC 6334I and AFGL 2591. Both single LOs and Spectral scans are available.

This program also provides a spectral map of rhoOph. The spectra are provided at the four positions indicated in Liseau et al. (2012).