PSF quality metrics in the problem of revealing Intermediate-Mass Black Holes using MICADO@ELT

Nowadays, astronomers perform point spread function (PSF) fitting for most types of observational data. Interpolation of the PSF is often an intermediate step in such algorithms. In the case of the Multi-AO Imaging Camera for Deep Observations (MICADO) at the Extremely Large Telescope (ELT), PSF interpolation will play a crucial role in high-precision astrometry for stellar clusters and confirmation of the Intermediate-Mass Black Holes (IMBHs) presence. Significant PSF variations across the field of view invalidate the approach of deconvolution with a mean PSF or on-axis PSF. The ignoring of PSF variations can be especially unsatisfactory in the case of Single Conjugate Adaptive Optics (SCAO) observations, as these sophisticated and expensive systems are designed to achieve high resolution with ground-based telescopes by correcting for atmospheric turbulence in the direction of one reference star. In plenty of tasks, you face the question: How can I establish the quality of PSF fitting or interpolation? Our study aims to demonstrate the variety of PSF quality metrics, including the problem of revealing IMBHs in stellar clusters.