Island of Manhattan “astronomical device”
Apparently the streets in Manhattan are at 29o degrees off earth’s axis. From:
From BldgBlog:
As it happens, then, Manhattan’s mathematically rational street grid is actually rotated 29º off the north-south axis – and this angle has interesting astronomical side-effects.
In other words, because of the off-center orientation of Manhattan’s street grid, you can only see the setting sun “down the middle of any crosstown street” on two specific days of the year: May 28 and July 13.