Comparison of the 268.149 GHz line profiles extracted for an aperture diameter of 0.″4 in VX Sgr observed at ∼1 km s⁻¹ resolution in November 2018 and July 2019 with the mid and extended configurations of the main array (upper and lower panels, respectively). The weak feature near −20 km s⁻¹ in the 2019 spectrum corresponds to the ν = 0, J_Ka,Kc = 9_5,5−10_4,6 transition oO SO₂ at 268168.335 MHz; it is also barely seen in the 2018 mid spectrum. The vertical lines are at the adopted new LSR systemic velocity.