Vilnius Dallmeyer Photoheliograph Solar Archive (1869–1874): Digital Collection of 283 Surviving Photographs

This repository contains the complete set of 283 surviving solar photographs obtained with the Vilnius Dallmeyer photoheliograph, the second photoheliograph in the world and the first constructed by John Henry Dallmeyer, taken between 1869 and 1874. The images are provided with their exact observation dates, offering a detailed chronological record of sunspot activity from this early phase of solar photography. Digitized and published here for the first time, they constitute the only preserved examples known today from a series that once comprised nearly 900 solar photograph. Further analysis of this unique dataset will be presented in a forthcoming article in the Journal of Astronomical History and Heritage (JAHH).