Аннотация:We present MASTER observations from inspecting the large error-box associated with LIGO/Virgo G270590, and our observational strategy. MASTER observed 6292 square degrees inside the 3σ error box. We present new optical sources detected during this inspection.https://doi.org/10.3847/2515-5172/abccc1https://iopscience.iop.org/article/10.3847/2515-5172/abccc1