2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/162347The 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.6 pages, 9 figures, 1 tableAstrophysicstext