Hα image of MyCn 18 taken through the narrowband F656N filter. The plate scale is 0﹩\farcs﹩0456 pixel⁻¹, and the image covers an area ﹩2\farcs 28\times 2\farcs 28﹩ (﹩500\times 500﹩ pixels). The linear streak in the upper right quadrant of the Hα image is due to imperfect removal of a cosmic‐ray event. A logarithmic stretch and reverse gray scale have been used in the image, and the maximum (black) and minimum (white) values of the surface brightness, respectively, are ﹩1.81\times 10﹩⁻¹¹ and ﹩3.67\times 10^{-15}﹩ ergs s⁻¹ cm⁻² arcsec⁻².