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We report on VLBI observations of OH masers in W49N. The angular sizes we measure for these masers, about 11 kpc distant, are greater than those of other closer OH masers. We believe that the masers have small intrinsic dimension, but suffer from heavy angular broadening by interstellar scattering. This is consistent with previous measurements of $H_2O$ masers in the same region whose sizes are thought to be dominated by the effects of scattering. We discuss the implications of this measurement for turbulence in the interstellar medium.
The masers are observed to have extremely narrow intrinsic linewidths. We suggest that, in future observations, narrower bandwidths and higher spectral resolution would increase sensitivity to faint maser features.
