The OSER project

The OSER project (Optical Scintillation by Extraterrestrial Refractors) is proposed to search for scintillation of extragalactic sources through the galactic -- disk or halo -- transparent $\mathrm{H\_2}$ clouds, the last unknown baryonic structures. This project should allow one to detect column density stochastic variations in cool Galactic molecular clouds of order of $\sim 3\times 10^{-5} \mathrm{g/cm^2}$ per $\sim 10 000 \mathrm{km}$ transverse distance.