May 23, 2026
Sun, shade, and comment-section chaos
Hengefinder: Finding When the Sun Aligns with Your Street
A dreamy sun-chasing map drops, and the comments instantly turn into a street-safety and phone-access war
TLDR: Hengefinder is a new tool that helps people find when the sunset lines up perfectly with their street, inspired by Manhattanhenge. The comments quickly stole the show, with users complaining about mobile access, asking for sunrise mode, and roasting the tradition of standing in traffic for the perfect photo.
A delightful little internet project about finding the perfect sunset lined up with your street somehow triggered exactly the kind of comment-section chaos the internet lives for. The tool, Hengefinder, was built after its creator got obsessed with Manhattanhenge—that brief, golden moment when the setting sun fits perfectly between Manhattan’s buildings. The idea is simple enough for non-astronomy people: figure out your street’s direction, compare it to where the sun sets, and boom, you’ve got your own local “henge.” But while the maker was busy wrestling with Earth-not-being-flat math, the community was busy doing what it does best: nitpicking, demanding features, and dropping trivia grenades.
The loudest grumbles? People locked out on mobile were not amused. Multiple commenters basically said: nice sunset app, shame we can’t actually use it on a phone while standing outside trying to look at the sunset. That sparked the biggest practical complaint by far. Then came the feature requests: one user wanted sunrise alignments too, pointing out that some cities get their best effect in the morning, not at sunset. Another turned the whole romance of Manhattanhenge into a public-safety PSA, calling out the annual tradition of people standing in the middle of the street to get the shot as straight-up wild. And for pure comment-section energy, one history-minded drive-by casually reminded everyone that Stonehenge is, technically, not a henge—which is exactly the kind of glorious nerd correction no internet discussion can resist.
Key Points
- •The article explains Hengefinder, a tool built to find dates when the setting sun aligns with streets in locations beyond Manhattan.
- •It identifies three core steps for the calculation: determine road bearing, determine the sun’s azimuth at sunset for each day, and match the angles by date.
- •The author built Hengefinder as an early project at the Recurse Center.
- •The article highlights practical challenges including non-flat roads, non-Cartesian behavior of latitude and longitude, and ambiguity in defining sunset.
- •It explains that naive bearing calculations using raw latitude and longitude differences are incorrect, and that longitude should be scaled by cos(latitude) before applying atan2.