The visual effect known as Manhattanhenge returns to New York City today and tomorrow. The Event—which was first named and noticed by Neil deGrasse Tyson—happens four times a year, twice with a half sun and twice with a full sun. It occurs when the sunset aligns perfectly with the city’s grid system, illuminating both the north and south sides of every cross street of the borough’s grid.

“It is a unique urban phenomenon in the world, if not the universe,” said  Tyson

The weather is forecast to cooperate for this phenomena, providing spectators a great view of the setting sun. During this event, half the sun is usually visible above the horizon while the other half is hidden below. The event happens 8:27pm tonight and tomorrow, although people should set up cameras and get a clear view of the sight plenty of time in advance of the sunset.

This is the last Manhattanhenge event of 2018. If you miss tonight’s view, you’ll need to wait until next May for the next opportunity to view it.

For the best view of Manhattanhenge, you should be as far east as possible, but be sure to pick a street where the view is clear across to New Jersey and the Hudson River. The best views  are on 57th, 42nd, 34th, 23rd, and 14th street.