Birr Castle Telescope.
This old photo I found in one of my albums. It shows a group of visitors to the "Great Birr Telescope" sometime probably in the 1870's. I don't know who the visitors are but the figure on the right (standing) is the Fourth Earl of Rosse. The figure on the left (with long beard) is Dr Otto Boeddicker. Boeddicker of course is famous for drawing his charts of the Milky Way from the North Pole to 10 degrees of South Declination as seen by the naked eye between 1884 and 1889, and published in 1892. I am very fortunate in having two original sets in my collection!