We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
"If Manhattan's streets were perfectly laid out on an east-west grid, Manhattanhenge would occur facing both east and west on the vernal and autumnal equinoxes."
That is wrong. On the dates of the equinox, the sun is positioned over the earth's equator and rises and sets precisely to the east and west, respectively, only if you are located on the equator. The sun never travels farther north than a latitude of 23.5 degrees (the Tropic of Cancer). The latitude of NYC is 40N. Consequently, the sun always rises and sets at an azimuth that is to the south of NYC.
There is only one place in the US where the sun ever rise directly to the east and sets directly in the west, and that is Hawaii, which is at latitude 19N. On two days each year, once in May and once again in July (in fact, that happens today for Honolulu on the island of Oahu) the sun rises directly in the east, passes directly overhead, and then sets directly in the west.
That applies to overhead at noon but not to rising and setting, which wander northwards and southwards more the higher your latitude.
In particular they pass exactly east and exactly west at any latitude.
Geometrical fact of the day: the sun rises in the northeast now, even in Australia. In Australia, though, it proceeds northwards and then sets in the northwest, giving a short Southern Hemisphere winter day.