Fermi trigger No 653072474: Global MASTER-Net observations report

MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB210911.71 (trigger No 653072474,19h 32m 21.60s , +15d 41m 24.0s, R=1.16) errorbox 33 sec after trigger time at 2021-09-11 17:01:43 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 29 deg. The sun altitude is -11.5 deg. The galactic latitude b = -2 deg., longitude l = 52 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1717728 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 39 | 2021-09-11 17:01:43 | MASTER-Tavrida | (19h 22m 56.19s , +15d 57m 57.5s) | C | 10 | 12.9 | 68 | 2021-09-11 17:02:12 | MASTER-Tavrida | (19h 22m 52.77s , +15d 59m 30.8s) | C | 10 | 13.0 | 102 | 2021-09-11 17:02:41 | MASTER-Tavrida | (19h 30m 01.45s , +15d 40m 57.4s) | P\ | 20 | 12.5 | 141 | 2021-09-11 17:03:20 | MASTER-Tavrida | (19h 30m 04.18s , +15d 42m 26.2s) | P\ | 20 | 12.3 | 237 | 2021-09-11 17:04:46 | MASTER-Tavrida | (19h 29m 59.60s , +15d 42m 33.7s) | P\ | 40 | 15.4 | 297 | 2021-09-11 17:04:46 | MASTER-Tavrida | (19h 29m 59.61s , +15d 42m 33.6s) | P\ | 160 | 16.3 | Coadd 301 | 2021-09-11 17:05:45 | MASTER-Tavrida | (19h 30m 04.14s , +15d 41m 30.9s) | P\ | 50 | 15.7 | 380 | 2021-09-11 17:06:54 | MASTER-Tavrida | (19h 29m 59.44s , +15d 40m 26.8s) | P\ | 70 | 16.3 | 479 | 2021-09-11 17:08:23 | MASTER-Tavrida | (19h 30m 06.28s , +15d 40m 44.3s) | P\ | 90 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.