Аннотация: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) started inspect of the Fermi GRB210228.28 (trigger No 636187116,06h 06m 28.80s , -41d 17m 24.0s, R=1) errorbox 34607 sec after notice time and 40338 sec after trigger time at 2021-02-28 17:50:49 UT, with upper limit up to 16.9 mag. Observations started at twilight. The observations began at zenith distance = 12 deg. The sun altitude is -8.3 deg. The galactic latitude b = -25 deg., longitude l = 248 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1557721 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________| _____________________|__________ ___________|_____________________ _______________|_____|_______|___ ____|________ 40369 | 2021-02-28 17:50:49 | MASTER- SAAO | (06h 01m 25.31s , -43d 08m 17.8s) | C | 60 | 16.3 | 40449 | 2021-02-28 17:52:09 | MASTER-SAAO | (06h 11m 27.87s , -41d 09m 11.1s) | C | 60 | 16.8 | 40608 | 2021-02-28 17:54:49 | MASTER- SAAO | (06h 01m 07.25s , -39d 08m 08.8s) | C | 60 | 16.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.