  An amateur astronomer in the modern world has the opportunity not only to
make visual observations for own interest, but can make scientific astronomical
observations and new discoveries in astronomy.
  In my example, as amateur astronomer and only through self-education, I
inform about my discoveries: of the possible dwarf nova on the old digitized
photographic plates and of new variable stars from sky surveys data by means of
data mining; how I discovered (in the images of the sky surveys): astronomical
transients, supernovae, planetary nebula candidates and new binary systems in
the data of Gaia DR2; I describe my discoveries of three novae in the Andromeda
Galaxy.
  I report about some of my scientific observations using remote telescopes: of
superhumps of cataclysmic variable stars; of echo outburst of AM CVn star; of
maximum brightness of blazars; of optical afterglows of gamma-ray bursts
(including GRB 221009A); of microlensing events; of rotation of near-Earth
asteroid 2022 AB. I also describe my photometric follow-up observations of
novae (including V1405 Cas and V1674 Her) and my astrometric observations of
Solar System objects (including the confirmation of objects posted at the
Confirmation Pages of the Minor Planet Center) including observations of comet
2I/Borisov, asteroids 2020 AV2 and (65803) Didymos. I also describe some of my
observations of occultations: of the star by asteroid (159) Aemilia, of the
star by Saturn's moon Titan and of Uranus by the Moon during total lunar
eclipse on November 8, 2022; and visual observations of variable stars, meteors
and sunspots (including during the transit of Venus in 2012).
  Some of my data already used in scientific papers, others were sent to the
databases. I share my experience of discovery and research of astronomical
objects and in my example, I show that an amateur astronomer can make a real
contribution to the science.
