2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/102627We give an introduction to interferometrical concepts and their applicability to Be stars. The first part of the paper concentrates on a short historic overview and basic principles of two-beam interferometric observations. In the second part, the VLTI/MIDI instrument is introduced and its first results on Be stars, obtained on alpha Ara and delta Cen, are outlined.To appear in proceedings of the Astronomische Gesellshaft meeting, 2004Astrophysicstext