Supermassive black hole binary (SMBHB) is a result of galaxies coalescing, when two supermas-
sive black holes form a hard binary with distances from kpc to pc. If the system reaches milliparsec
separation, the black holes eventually merge. There are a growing number of few sub-pc SMBHB
candidates, one of which according to Jiang et al (2022). will merge within three years. We have
performed the monitoring of the host galaxy SDSSJ143016.05+230344.4 during its visibility with
H.E.S.S. in April–July 2022. Given that subsequent follow-up observations with optical and X-ray
instruments have not confirmed some of the predictions initially presented, and time constraints
for the merger beyond 2022 are less precise, we changed our monitoring and follow-up strategy
for further observations. In this work we present our results of the monitoring and discuss the
prospects of these kind of observations with imaging atmospheric Cherenkov telescopes.