Optical and near-IR observations of SN 1987A.

The ring collision in SN 1987 offers an opportunity to study the development of radiative shocks in real time. We here review the optical and near-IR observations of the collision and discuss them in relation to observations at other wavelengths. In particular, the shock diagnostics provided by the coronal lines, the line profiles and the fluxes are discussed. [ABSTRACT FROM AUTHOR]