  In this work, we focused on observations of six trans-Neptunian objects
(TNOs) whose apparent magnitudes are brighter than 20 mag. We present the
results of astrometric and photometric observations of (134340) Pluto, (136108)
Haumea, (136472) Makemake, (136199) Eris, (90482) Orcus and (20000) Varuna
obtained at the Kyiv comet station (Code MPC 585) in 2017-2019. For
observations, we used the 0.7-m reflector AZT-8 with the FLI PL4710 CCD camera
and filters of the Johnson-Cousins photometric system. From our images, we
measured the objects astrometric positions, calculated apparent magnitudes in
the BVRI (mostly R) bands using the aperture photometry method, and found the
absolute magnitudes together with the colour indices in several bands.
Analysing our results, we investigate the limitation on the astrometry and
photometry of faint objects with the 0.7-m telescope.
