Аннотация:MASTER OT J203053.79+384020.1 discoveryMASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 20h 30m 53.79s +38d 40m 20.1s on 2019-07-18.92684 UT.The OT unfiltered magnitude is 14.9m (limit 19.4m).This flash is registered in the error box GW S190718y.The OT is seen in 2 images. There is no minor planet at this place.We have reference image without OT on 2019-07-09.14716 UT with unfiltered magnitude limit 19.7m.The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/203053.79384020.1.png