2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33754We present a characteristic algorithm for computing the perturbations of a Schwarzschild spacetime by means of solving the Teukolsky equations. Our methods and results are expected to have direct bearing on the study of binary black holes presently underway using a fully {\em nonlinear} characteristic code \cite{Gomez98a}.2 pages, contribution to the 9th Marcel Grossmann meeting (MG9), Rome, July 2000General Relativity and Quantum Cosmologytext