LIGO/Virgo S230620af: Global MASTER-Net observations report

MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the LIGO/Virgo S230620af errorbox 32 sec after notice time and 179 sec after trigger time at 2023-06-20 04:33:41 UT, with upper limit up to 18.4 mag. The observations began at zenith distance = 59 deg. The sun altitude is -82.4 deg. The galactic latitude b = 60 deg., longitude l = 177 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=12190 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 270 | 2023-06-20 04:33:41 | MASTER-OAFA | (16h 02m 34.91s , +21d 39m 05.3s) | C | 180 | 18.4 | 448 | 2023-06-20 04:37:30 | MASTER- | (10h 37m 59.66s , +40d 35m 01.8s) | C | 80 | 16.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.