2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/424We have measured the properties of the diffractive scintillation toward the Vela pulsar under the extremely strong scattering conditions encountered at 660 MHz. We obtain a decorrelation bandwidth of $ν_d = 244 \pm 4$ Hz and diffractive decorrelation timescale of $t_{\rm diff} = 3.3\pm 0.3$ s. Our measurement of the modulation indices $m=0.87\pm 0.003\pm 0.05$ and $m=0.93\pm 0.03 \pm 0.05$ (one for each polarization stream), are at variance with the modulation index of the Vela pulsar obtained at 2.3 GHz by Gwinn et al. (1997) {\it if} the deviation from a modulation index of unity is ascribed to a source size effect.4 pages, 1 figure, to appear in Proc. IAUC177 "Pulsar Astronomy - 2000 and Beyond" Eds. M. Kramer, N. Wex & R. Wielebinski (ASP Conf. Series; uses newpasp.sty)Astrophysicstext