Interstellar extinction toward symbiotic stars

Using diffuse interstellar bands (DIBs) at 5780 A, 5797 A and 6613 A, visible in the high resolution spectra, and measuring their equivalent widths, we estimate the interstellar extinction toward seven symbiotic stars. We find $E_{B-V}$= $1.28 \pm 0.10$ for AS 289, $E_{B-V}$= $1.55 \pm 0.10$ for BI Cru, $E_{B-V}$= $0.63 \pm 0.10$ for HD330036, $E_{B-V}$= $0.33 \pm 0.05$ for V2756 Sgr, $E_{B-V}$= $0.30 \pm 0.05$ for V2905 Sgr, $E_{B-V}$= $1.52 \pm 0.11$ for V417 Cen, $E_{B-V}$= $0.81 \pm 0.10$ for PN Sa 3-22. The derived values are in agreement with the extinction through the Galaxy.