Manhattanhenge, New York City's famous solstice spectacular, is fast approaching. Here are this year's dates, according to the : What is Manhattanhenge? It's the four days of the year when the sunset aligns with Manhattan's street grid, setting directly over the borough's east-west streets. Also known as the Manhattan Solstice, this astronomical phenomenon portends . Each set of dates—late spring and early summer—features two chances for the Instagramming masses to capture a #hashtagworthy photo. There's "Full Sun on the Grid" (pictured above), where the whole of the sun appears to balance on horizon before sinking below, and "Half Sun on the Grid," when half the sun sits on the horizon and half below. The Hayden Planetarium of the phenomenon every year on its website and is considered the official source as to the event's precise timing.The Best Places to See ManhattanhengeThe Hayden Planetarium page recommends finding a spot as far east as possible in Manhattan that still has a view of New Jersey across the Hudson River. We've found that the best views are at the following spots (our picks also take into consideration photogenic Manhattan architecture): These streets are best because, as major east-west thoroughfares, they're wider than most of the other city streets that also fall within the part of the grid that aligns with phenomenon.BackstoryThe island of Manhattan doesn't align perfectly north-south. It's rotated off true north by roughly 29° clockwise. Likewise, much of Manhattan's street grid from Houston Street to 155th Street is rotated to match, per the , which established the City's street plan.Because of that, the sunset aligns with the grid when its azimuth is 29° north of due west, about 20 days before and after the summer solstice. It's therefore possible to observe the phenomenon on any east-west street on the grid that has an unobstructed view over the Hudson River to New Jersey—though you can sometimes observe it between buildings even without a river view, as in the photo taken in Central Park above.For practicality's sake, though, those wider streets mentioned above have the best views and afford more room for crowds. Speaking of which, please be careful not to block traffic or stand in the street when you don't have a crossing signal. It's a stellar view, but we don't want you to get hurt trying to capture it.Time It RightArrive early if you want a good spot for photos—half an hour before should be fine. Here are Manhattanhenge's exact times as calculated by the Hayden Planetarium:Half Sun on the Grid Full Sun on the Grid Good luck out there. Fingers crossed for warm weather and clear skies, without which Manhattanhenge is a bust. And be sure to tag your photos —we'd love to share them on !