Mid-infrared visibility measurements of evolved stars

We have used Denver University's Ten-and-Twenty Micron Camera at the Wyomin g Infrared Observatory to image 12 evolved stars at 11.5 mu m. We have obta ined both visibility data and photometric magnitudes from these images. We have partially resolved the circumstellar dust shell for eight of these 12 stars: alpha Ori, VY CMa, IRC +10216, chi Cyg, IK Tau, NML Cyg, mu Cep, and IRC +10420. We compare our data to published data and to visibility curves predicted by radiative transfer models in the literature.