Longest day

June 16 falls quite close (four or five days) to the summer solstice, as Stephen notes at the end of Proteus: "By the way next when is it Tuesday will be the longest day." Dublin lies north of the 53rd parallel (a line that passes near the southern end of Hudson Bay), meaning that in late June its days are quite long indeed. At the solstice the sun can be seen for nearly 17 hours. It sets in Nausicaa.

John Hunt 2015

Dublin at the summer solstice. Source: viewfinder.expedia.com.