Using an airglow imager from OI 630 nm channel at the Southern Space Observatory (SSO; 29.44°S, 53.82°W) in São Martinho da Serra, southern Brazil, thermospheric concentric gravity waves (CGWs) were observed during 17–18 September 2023. The analysis revealed that the OI 630 nm airglow images were significantly contaminated by OH airglow emissions (715–930 nm), resulting in the projection of mesospheric CGWs (observed in the OH layer at ~87 km altitude, DOI: 10.5446/69990) onto the thermospheric OI 630 nm emission layer (~250 km altitude). Despite this contamination, westward- and northwestward-propagating thermospheric CGWs were unambiguously identified. |