Speaker
Description
We present 283 surviving solar photographs obtained during the second half of the 19th century with the Vilnius Dallmeyer photoheliograph, the second built worldwide and the first constructed by John Henry Dallmeyer. We briefly outline the historical context of the instrument, its technical characteristics, and the observational program carried out at Vilnius Observatory, which became one of the earliest centers of systematic solar photography. The best-preserved series provides a rare and nearly continuous record of sunspot activity in the Nordic-Baltic region. We present the cataloguing and preliminary assessment of this material and discuss its relevance for historical solar research and for ongoing efforts to reconstruct long-term solar variability through the integration of early photographic datasets.