Four-channel wide-field cluster for survey tasks and synchronous multicolor photometry

A new wide-field optical instrument of the Institute of Astronomy of the Russian Academy of Sciences (INASAN) is described. It has been implemented under the bilateral Russia--Uzbekistan collaboration in astronomy in 2023–2025. The instrument comprises four identical wide-field 28-cm aperture telescopes on a common mount designed for all-sky surveys and photometry. For a single exposure, the cluster takes an image of a 7 square degree field in four photometric bands simultaneously with a 1.26 $''$/px scale. The technical and optoelectronic characteristics of the cluster are presented and discussed. The plan is to install the cluster at the Maidanak Astronomical Observatory, which has a large amount of clear night time (about 2500 hours per year) with a median seeing of $0\,.\!\!^{\prime\prime}7$. The INASAN cluster will become one of the most informative positional photometric multiband observing systems in Russia. It will also be useful in a global network of multiband wide-field optical instruments including the BRICS astronomical network.