Lord Rosse's drawing of M51

In 1845-1850 Lord Rosse made a couple of drawings of the galaxy M51 (figure left) with the, at that time, largest telescope in the world. (PiP 1 and 2). This telescope we visited in 2015 in Birr (Ireland). PiP 3 shows an old drawing of the observatory. More drawings are shown in the link below. These drawings showed for the first time the spiral structure in a nebula.

On the right is a cropped version of the picture shown in PiP 4

articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?2012JAHH...15...19S&defaultprint=YES&filetype=.pdf