Swift GRB 230723B: Global MASTER-Net observations report

MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 230723B ( K. L. Page et al., GCN 34234) errorbox 18882 sec after notice time and 18900 sec after trigger time at 2023-07-23 16:57:33 UT, with upper limit up to 19.3 mag. Observations started at twilight. The observations began at zenith distance = 42 deg. The sun altitude is -13.0 deg. The galactic latitude b = 25 deg., longitude l = 12 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2243736 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 18990 | MASTER-SAAO | C | 180 | 18.1 | 18990 | MASTER-SAAO | C | 180 | 19.1 | 19201 | MASTER-SAAO | C | 180 | 18.4 | 19201 | MASTER-SAAO | C | 180 | 19.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.