Rotation curves for H30α and H26α masers in MWC 349A. (a) The projected distance is calculated as ﹩\sqrt{{({\rm{\Delta }}{\rm{R}}.{\rm{A}}.\cos (\mathrm{decl}.))}^{2}+{\rm{\Delta }}\mathrm{decl}{.}^{2}}﹩. (b) Distance to the polar axis is calculated as the perpendicular distance from the maser point to the line that is both orthogonal to the line of best fit for the disk masers and that intersects the best-fit line at the center. In both panels the color indicates the velocity of the masers in km s⁻¹.