GRB 210730A: Campo Imperatore optical observations

On 2021-07-30 we observed the field of GRB210730A (Sonbas et al., GCN Circ. 30548; Prasad et al., GCN Circ. 30555; Wood et al., GCN Circ. 30577) with the 0.9m Schmidt Telescope of the INAF - Astronomical Observatory of Abruzzo located at 2150 meters a.s.l. at Campo Imperatore (Italy) and equipped with a 4096x4096 CCD, covering a field of view of 1.15×1.15 square degrees. A series of optical images of the field have been obtained with the r-Sloan and z-Sloan filters on 2021-07-30. The observation started at 19:50:29 UT (about 15 hr after the burst) for a total exposure time of 26x180s in r band and 15x180s in z band, respectively. A preliminary analysis does not show any optical counterpart candidate within the XRT error circle (https://www.swift.ac.uk/xrt_positions/01062150/ ).