I tried to identify some faint stars on my image. I found SDSS image of NGC 2770 and labeled some faint sources (down to R band limit of our combined image). These are labeled on both images (white and red lines). It seems that faintest stars detected here in Brno (light polluted) on 40cm reflector using CCD ST7XMEi with R Kron-Cousins filter (not unfiltered!) is 19-19.5 mag (full Moon and not good weather conditions). Yes, the price we pay is 4 hours of total exposure. This image is combined using 3 nights data together.