Knowing the relative energy carried away from the supernova by photons and by neutrinos (1:100), photon and neutrino energy spectra, neutrino cross section and

Knowing the relative energy carried away from the supernova by photons and by neutrinos (1:100), photon and neutrino energy spectra, neutrino cross section and the size of the IMB and Kamiokande detectors you can estimate the flux of photons through some hypothetical light detector (sometimes called a "telescope"). Probably some model for interstellar gas is needed to account for scatter or absorb the photons.