An Interferometric Survey of Mira Variables and M Supergiants

We present preliminary results from an imaging survey of bright northern Mira variables and Supergiants. Diffraction-limited images of Mira exhibit the same elongation along PA 120° as observed in previous observations. Of the other Mira variables observed, R CasIs unambiguously detected as non-spherically symmetric. Our observations of α-Her are consistent with there being a ‘hot-spot’ on its surface, similar to those we have previously detected on Betelgeuse.