The term, made popular by Hayden Planetarium Director Neil deGrasse Tyson, refers to the four days each year the sunset aligns perfectly with the New York City street grid.
It creates a striking image similar to how Stonehenge looks during the sunrise on the summer solstice.
Manhattanhenge already happened once this year, on May 29 and 30, though it was too cloudy to see.
Friday was the best night of the year to observe Manhattanhenge, according to deGrasse Tyson, when the full sun was on the grid.
Saturday night will be a half sunset on the grid at 8:25 p.m.
DeGrasse Tyson has some advice for New Yorkers wanting to get a good view.
"Arrive a half-hour earlier than the times given below. For best effect, position yourself as far east in Manhattan as possible. But ensure that when you look west across the avenues you can still see New Jersey. Clear cross streets include 14th, 23rd, 34th. 42nd, 57th, and several streets adjacent to them. The Empire State building and the Chrysler building render 34th street and 42nd streets especially striking vistas," he said.