Overlay of the velocity-integrated total-intensity images of ²⁸SiO maser transitions at λ3 mm (in yellow, observed on January 24, 2011, integrated over the velocity range of −14.2 to +27.9 km s^-1) and λ7 mm (in blue, observed on October 7, 2002, integrated over the velocity range of −48.1 to +62.3 km s^-1): (left) λ3 mm v = 1, J = 2−1 and λ7 mm v = 1, J = 1−0; (center) λ3 mm v = 1, J = 2−1 and λ7 mm v = 2, J = 1−0; (right) λ3 mm v = 1, J = 2−1 and both λ7 mm v = 1 and v = 2, J = 1−0. The cross indicates the estimated position for Source I.