  The primary task of the Debrecen Heliophysical Observatory (DHO) was to
produce the detailed and reliable photographic documentation of the solar
photospheric activity since 1958. This long-term effort resulted in various
solar catalogues based on ground-based and space-borne observations. The DHO
hosts solar-image databases containing heritages of two former Hungarian
observatories. One of the sets of drawings was observed between 1872 and 1891
at the \'Ogyalla Observatory (now Hurbanovo, Slovakia) founded by Mikl\'os
Konkoly-Thege (1842-1916). We briefly summarize the history of the events that
resulted in the longest photographic sunspot database available at the DHO at
present, and we show the basic role of Dr. Mikl\'os Konkoly-Thege in this
achievement.
