We obtained spectro-interferometric observations in the visible of β
Lyrae and Ï… Sgr using the instrument VEGA of the CHARA interferometric
array. For β Lyrae, the dispersed fringe visibilities and differential
phases were obtained in spectral regions containing the Hα and HeI 6678
lines and the Hβ and HeI 4921 lines. Whereas the source is unresolved in
the continuum, the source of the emission lines is resolved and the photocenter
of the bulk of the Hα emission exhibits offsets correlated with the
orbital phase. For υ Sgr, both the continuum and Hα sources are
resolved, but no clear binary signal is detected. The differential phase shift
across the line reveals that the bulk of the Hα emission is clearly
offset from the primary