The Helium and Lead Observatory (HALO) is a dedicated supernova neutrino detector that is presently under construction underground at SNOLAB in the Creighton Mine in Sudbury Ontario Canada.

It uses 76 tonnes of annular lead blocks instrumented with 128 tubular Helium-3 neutron detectors to detect neutrinos from supernovae within our galaxy. As a part of the worldwide Supernova Early Warning System (SNEWS), it will help detect supernovae by their neutrino burst, before their light reaches Earth, allowing time to notify both professional and amateur astronomers.