Looking for fast optical bursts from FRB121102: Case study for a small telescopes with sub-second temporal resolution

To assess the potential of small telescopes for high temporal resolution astrophysics, we observed the field of FRB 121102 repeating source of fast radio bursts (FRBs) on a 50-cm D50 telescope of Ondejov observatory, equipped with a fast frame rate electron-multiplying charge coupling device (EMCCD) detector. In three nights of observations, we did not detect any optical flares from the source, which allows us to place an upper limit of 10 mJy for brightness of possible fast optical events on a time scale of 10 ms. We also characterize the apparent brightness stability of field stars on the same time scale in order to investigate the potential of such telescopes for detecting faint optical variability on a subsecond time scale.