Privacy

What Henge Days records while you use it, and why.

What is recorded

The addresses and place names you search for, where they resolved to, and whether a building outline was found. This is how search problems get found and fixed.
For a plan along a street: the street's name, the distance between the two ends, the day, and whether the street was found. The two addresses themselves are kept only as searches, as above.
Which features you use: outline loads, calendars computed, calendar files downloaded, walls selected, tabs opened.
When you press Share, the link that was copied. For the first page you open on each visit, the page's address and the name of the website you came from, such as google.com, without the rest of that site's address.
When a chat or social app such as Messages, Slack or WhatsApp fetches a page of Henge Days to show a preview of a link, the name of the app and the page's address. Nothing about the person who pasted the link is recorded.
When an AI assistant such as ChatGPT, Claude or Perplexity, or a search engine's crawler, fetches a page, the agent's name, the page's address and whether it took the page's Markdown form. Nothing about the person who asked the assistant is recorded.
For each building page viewed, the building's name, the center of its outline, its next head-on day and the dates of each wall's head-on windows in the next 12 months are kept for 60 days, so that a shared link to the page, or to one wall and date on it, shows them in its preview. For each street planned, the street's name, the coordinates of its two ends, the day, the count of walls that get the sun and the first three stops are kept the same way. Nothing about who viewed the page is kept with them.
A random id stored in your browser, so that one visit can be told apart from another. It is not linked to your name or email unless you give them in feedback.
Your browser type, the country your connection comes from, and the version of the site you were using.
Google Analytics, a service from Google, records which pages are viewed and standard visit information such as browser and country, under Google's terms. It receives the web address of each page, and the address of a building page contains the place you searched for. Henge Days does not send it your email address or anything else you type.
Anything you type into the feedback form, with the page and building you were looking at. Your email address is kept if you enter it, or if you are signed in. Each message is also emailed to the site's owner, and the owner is emailed when an account is created.

If you sign in

Your email address is stored with your account. Sign-in emails are sent by Supabase, the service that holds the account database.
The buildings and henge days you save are stored under your account, with the building outline, the wall they refer to, any note you add, and whether you marked a day as shot or missed.
If you open the calendar feed in the planner, a secret link is made for your account. Anyone who has the link can read your saved days. Each time a calendar app reads it, the time of the read is recorded. Get a new link from the planner to stop the old one.
Usage records and feedback made while signed in are linked to your account instead of only to the browser id. The owner can see which account a piece of feedback came from.
A reply from the owner to your feedback is stored with it and shown in the feedback dialog. The time you first open a reply is recorded, so the Feedback button can stop counting it as unread.
Signing out ends the link. To delete your account and everything under it, use the Feedback button and ask.

What is not recorded

Your IP address is not stored.
Your precise location is not requested. The map's locate button, if you use it, stays in your browser.
To show a cloud forecast, the coordinates of a wall and the time of its head-on minute are sent to Open-Meteo, the weather service. No account or browser id goes with them.
The address you enter in the newsletter form goes to Substack, the service that sends the Henge Days newsletter, under Substack's terms. Henge Days does not record it, and your account on Henge Days is not subscribed to the newsletter. Henge Days records that a form was sent, and whether you opened or closed the newsletter banner at the top of an article. Your browser keeps when you closed the banner, or that you subscribed, so the banner stays hidden.
No advertising, and nothing is sold or shared. Google Analytics, listed above, is the only service from another company that records visits.

How long it is kept

Usage records are kept for up to 12 months. Feedback is kept until it has been dealt with and for 12 months after that.

Questions

Use the Feedback button on any page.

Terms and accuracy

How the dates and times on Henge Days are made, what they leave out, and the terms for using them.

This page is written in plain words. It is not legal advice.

What the dates are

Every date and time on Henge Days is computed. Nobody has stood at a given building on a given date to check it.

The sun's position comes from the NOAA solar position algorithm, accurate to about a hundredth of a degree. Refraction, the bending of light near the horizon, is included. This is the most reliable part of the result.
Building outlines come from OpenStreetMap, a map drawn by volunteers. An outline can be missing, simplified, a few meters out of place, or rotated by a degree or two.
A one degree error in the direction a wall faces moves the head-on moment by about four minutes. It can move a henge window by several days.
Addresses are looked up with public geocoders: Nominatim, the US Census Bureau geocoder and Photon. A search can land on the wrong building or on a range of addresses. Henge Days shows a warning when a match is known to be approximate or shared.

What is not included

Terrain and the horizon. Sunrise and sunset here mean the sun crossing a flat horizon. Hills, other buildings and trees can block a low sun for minutes or for the whole event.
Weather. The cloud figures shown for the next ten days are forecasts from Open-Meteo for that minute. A forecast can be wrong on the day. Haze, fog and smoke are not shown.
Access to the place you would stand: closures, traffic, construction, private property and local rules.
Clock times use the time zone of the building's location from the IANA time zone database (the standard list of world time zones), with daylight saving time applied. Check the time zone if the building is near a time zone border.

No warranty

Henge Days and everything it shows are provided as is. There is no warranty of any kind, express or implied, that the information is accurate, complete, or fit for any purpose.

Your responsibility

Check a location yourself before you rely on a date, travel to it, or plan a shoot around it. You are responsible for your own safety, for having the right to be where you stand, and for your own costs. Do not stand in a road to take a picture.

Liability

To the extent the law allows, the operator of Henge Days is not liable for any loss, injury, damage, expense or disappointment that arises from using the information on this site. This applies whether the information turns out to be accurate or not. It includes travel and booking costs and a missed sunrise or sunset.

Changes to the service

Henge Days can change, give different results, or stop at any time, without notice. Results for a building can change when its outline is edited in OpenStreetMap.

Map and address data

Building footprints are © OpenStreetMap contributors and available under the Open Database License (ODbL). Geocoding is by Nominatim, Photon and the US Census Bureau, and the basemap is by OpenFreeMap. Each of these services has its own terms.

Acceptable use

The Henge Days API is private and serves only the pages of this site. Do not scrape the site, call the API from scripts or other programs, or download results in bulk.

Questions

Use the Feedback button on any page.

Admin Dashboard

What needs a look since your last visit, then the site's health, where visitors come from, what they do, the feedback and accounts, and what Cloudflare and Supabase are costing.

Planner

Your buildings, with the map, the walls and the days you plan to be there.

Articles · October 17, 2026

Map of the Princeton University Chapel in Henge Days, with its west-southwest wall highlighted in pink and every wall labeled with its bearing. — The Princeton University Chapel, the first building in the list, in Henge Days. Pink marks the walls the evening sun lines up with on First-Year Families Weekend.

Princeton First-Year Families Weekend, November 6 and 7, 2026: four buildings to photograph on campus and in the town of Princeton

Four walls on the Princeton University campus and in the town of Princeton that line up with the low sun during First-Year Families Weekend, November 6 and 7, 2026, with the weekend's listed events, ten more walls in low sun and a spot for the family photo. All times are Eastern Standard Time.

For November 6 to 7, 2026.

First-Year Families Weekend at Princeton University is Friday, November 6, and Saturday, November 7, 2026. The four buildings below have a wall that faces the low sun on those days: three on the campus and one in the town of Princeton. Ten more campus walls get the sun a little higher, 6 to 10 degrees up. Post your pictures with #HengeDays.

Every time in this guide is US Eastern Standard Time (EST). Daylight saving time ends on November 1, so the clocks have already changed by the weekend. One pick is a morning wall, at 6:52 or 6:53 AM EST. The other three are evening walls, between 4:12 and 4:36 PM EST.

The weekend's schedule

The University's First-Year Family Weekend site at ffw.princeton.edu did not load from where this guide was written. The events below come from search results that summarized its event pages on October 17. The results did not include the full Saturday program or the time of the Saturday brunch, so this list names only what they showed. Check times and places at ffw.princeton.edu before you plan around them.

Friday, November 6, 9:00 AM to 5:00 PM EST: check-in at East Pyne and Chancellor Green Library. Before it, Princeton Stadium's southeast corner at 6:53 AM, golden light.
Friday, November 6, 9:30 AM to noon: open house at the Pace Center for Civic Engagement. 10:00 to 10:45 AM: open house at the Carl A. Fields Center for Equality and Cultural Understanding.
Friday, November 6, 10:00 AM to 3:00 PM: the Cotsen Children's Library is open.
Friday, November 6, 10:00 AM to 7:30 PM: Open Studio Hours at the Princeton University Art Museum. The museum is a short walk south of the Chapel. Photograph the Chapel at 4:23 PM, then go to the museum before it closes. The Suzanne Patterson Center wall in town comes first, at 4:12 PM, and the building on Woodland Way last, at 4:35 PM.
Saturday, November 7, 8:30 AM to 2:00 PM EST: check-in at East Pyne and Chancellor Green Library, where families pick up meal tickets for the Saturday brunch. You need to check in only once for the weekend. Before it, Princeton Stadium at 6:52 AM, golden light.
Saturday, November 7, noon to 5:00 PM: Princeton plays Dartmouth in football at Princeton Stadium. The weekend's event page gives that window, and the kickoff time can change. The Saturday evening walls fall during the game, at 4:13 to 4:36 PM. If you go to the game, photograph them on Friday.
Between events: the town of Princeton faces the campus across Nassau Street. Part 2 says what is there.

Part 1: the campus

The three campus walls are spread out. The Chapel is in the middle of the campus, next to Firestone Library and Dickinson Hall. Princeton Stadium is on the east side, south of Ivy Lane. The building on Woodland Way is at the south end, between Washington Road and Tilghman Walk, east of Yeh College.

1 Princeton University Chapel

Princeton University, Princeton, New Jersey

Wall: west-southwest, facing 245°
Sun: The low evening sun lines up with this wall on Nov 6 to 7. Best: Saturday, November 7 at 4:25 PM, 3.5° above the horizon.
Leaves: A guide published September 18 puts New Jersey's statewide peak between October 19 and 29, with the south of the state a few days later (The Sun Newspapers). Princeton is in central New Jersey, so by November 6 and 7 expect late color and falling leaves.
Where to stand: Stand on the campus walks west-southwest of the Chapel's west end, with the sun behind you. The sun lines up with the wall at 4:23 PM EST on Friday and 4:25 PM EST on Saturday, 3.9 and 3.5 degrees up. These are golden days: at the head-on moment the sun is up to 6 degrees up. The sun reaches 20 m of the 31 m of wall that faces this way. Morrison Hall rises toward the sun. OpenStreetMap has no height for it, and with an estimated height its roofline is at 1.6 degrees, below the sun on both days. Computed from the building outline and the sun's position, and not checked on the ground.

The University Chapel was designed by Ralph Adams Cram in English Gothic style and completed in 1928. It replaced Marquand Chapel, which burned in 1920. It seats about 2,000 people (Wikipedia). The wall that lines up is the west end of the nave, toward the walks on the Chapel's west side, with two short steps in the side walls that also face west-southwest.

Map of Princeton University Chapel in Henge Days, with the west-southwest wall highlighted and every wall labeled with its bearing — The building page in Henge Days. The highlighted walls face 245°, toward the sunset on the days in the row below; every wall carries its bearing.

Mon, Nov 2 to Tue, Nov 17, 202616 evenings · best Tue, Nov 17

4:38 PM Golden sunset, sun 0° up WSW 245° wall

Its row in the Henge days list, with the time of the head-on moment on the best day. Save keeps that day in your planner, which can send it to your calendar app. Saving asks you to sign in with an email link; there is no password.

A year of head-on days for each wall of Princeton University Chapel — The year for every wall of the building. Each row is a wall; the colored runs are its henge, golden and low-sun days.

Open this wall in Henge Days

Family photo spot. Stand the family on the walks a few steps out from the Chapel's west end, turned partway toward the camera. The photographer stands west-southwest of them, with the sun low behind and to one side, which lights faces and the stone behind them in the same warm light. Go on Friday at 4:23 PM EST, when the sun is 3.9 degrees up. The Art Museum is open until 7:30 PM that day. Saturday at 4:25 PM works too, if you are not at the game. Post it with #HengeDays. Computed from the building outline and the sun's position, and not checked on the ground.

2 Princeton Stadium

Princeton University, Princeton, New Jersey

Wall: east-southeast, facing 114°
Sun: The low morning sun lines up with this wall on Nov 6 to 7. Best: Saturday, November 7 at 6:52 AM, 2.4° above the horizon.
Leaves: A guide published September 18 puts New Jersey's statewide peak between October 19 and 29 (The Sun Newspapers). Expect late color in Princeton on November 6 and 7.
Where to stand: Stand on the open campus ground east-southeast of the stadium's southeast corner, between the stadium and Garage Drive, with the sun behind you. Stay out of Garage Drive. The sun lines up with the wall at 6:53 AM EST on Friday and 6:52 AM EST on Saturday, 2.8 and 2.4 degrees up. These are golden days: at the head-on moment the sun is up to 6 degrees up. The whole 25 m of the wall is lit, and nothing in the outlines stands in the way. On Saturday this is about five hours before the game window opens, so the gates are likely closed. Photograph the wall from outside. Computed from the building outline and the sun's position, and not checked on the ground.

Powers Field at Princeton Stadium opened on September 19, 1998, on the site of Palmer Stadium, and seats 27,800 (Wikipedia). OpenStreetMap draws the stadium without a name. The wall that lines up is a 25 m section at the southeast corner of the stands, toward Garage Drive. On Saturday the stadium hosts the football game against Dartmouth.

Map of Princeton Stadium in Henge Days, with the east-southeast wall highlighted and every wall labeled with its bearing — The building page in Henge Days. The highlighted walls face 114°, toward the sunrise on the days in the row below; every wall carries its bearing.

Fri, Oct 30 to Sat, Nov 14, 202616 mornings · best Sat, Nov 14

6:44 AM Golden sunrise, sun 0° up ESE 114° wall

Its row in the Henge days list, with the time of the head-on moment on the best day. Save keeps that day in your planner, which can send it to your calendar app. Saving asks you to sign in with an email link; there is no password.

A year of head-on days for each wall of Princeton Stadium — The year for every wall of the building. Each row is a wall; the colored runs are its henge, golden and low-sun days.

Open this wall in Henge Days

3 The five-story university building on Woodland Way

Princeton University, Princeton, New Jersey

Wall: west-southwest, facing 247°
Sun: The low evening sun lines up with this wall on Nov 6 to 7. Best: Saturday, November 7 at 4:36 PM, 1.6° above the horizon.
Leaves: A guide published September 18 puts New Jersey's statewide peak between October 19 and 29 (The Sun Newspapers). Expect late color in Princeton on November 6 and 7.
Where to stand: The wall is a 20 m section set back in a notch at the building's northwest corner, toward Tilghman Walk. Stand on the walk west-southwest of the notch, between the building and Tilghman Walk, with the sun behind you. Stay out of Woodland Way and Washington Road on the other side of the building. The sun lines up with the wall at 4:35 PM EST on Friday and 4:36 PM EST on Saturday, 2.0 and 1.6 degrees up. These are golden days: at the head-on moment the sun is up to 6 degrees up. The sun reaches 10 m of the 20 m wall. Kanji Hall rises toward the sun. OpenStreetMap has no height for it, and with an estimated height its roofline is at 1.1 degrees, 0.9 degrees below the sun on Friday and 0.5 on Saturday. The trees of the south campus are not part of the check and can take this light. Computed from the building outline and the sun's position, and not checked on the ground.

A five-story university building on Woodland Way, between Washington Road and Tilghman Walk at the south end of the campus, east of Yeh College and New College West. OpenStreetMap gives it no name, a height of 16 m and five levels. Addy and Aliya Kanji Hall is the next building toward the evening sun, and the walks between them are campus grounds.

Map of The five-story university building on Woodland Way in Henge Days, with the west-southwest wall highlighted and every wall labeled with its bearing — The building page in Henge Days. The highlighted walls face 247°, toward the sunset on the days in the row below; every wall carries its bearing.

Wed, Oct 28 to Wed, Nov 11, 202615 evenings · best Wed, Nov 11

4:42 PM Golden sunset, sun 0° up WSW 247° wall

Its row in the Henge days list, with the time of the head-on moment on the best day. Save keeps that day in your planner, which can send it to your calendar app. Saving asks you to sign in with an email link; there is no password.

A year of head-on days for each wall of The five-story university building on Woodland Way — The year for every wall of the building. Each row is a wall; the colored runs are its henge, golden and low-sun days.

Open this wall in Henge Days

Part 2: the town of Princeton

The town starts across Nassau Street from Nassau Hall and the front campus. Palmer Square, with its shops, restaurants and the Nassau Inn, opens off Nassau Street opposite the campus. Witherspoon Street runs north from Palmer Square to the Princeton Public Library on Hinds Plaza. Nassau Presbyterian Church is on Nassau Street. At the west end of Nassau Street, where it meets Stockton Street and Bayard Lane, stands the Princeton Battle Monument. Between the Friday open houses and the evening walls, or after Saturday's check-in, this is where to walk and eat. Most of the town's walls that line up this weekend are shop fronts on Nassau Street and Palmer Square with taller buildings toward the sun, so one town wall makes the list.

4 The Suzanne Patterson Center on Monument Drive

Princeton, New Jersey

Wall: west-southwest, facing 243°
Sun: The low evening sun lines up with this wall on Nov 6 to 7. Best: Saturday, November 7 at 4:13 PM, 5.4° above the horizon.
Leaves: A guide published September 18 puts New Jersey's statewide peak between October 19 and 29 (The Sun Newspapers). Expect late color in the street trees of the town on November 6 and 7.
Where to stand: The wall is the building's west side, 34 m in three sections. Stand on the footpath that runs past the building's west side, west-southwest of the wall, with the sun behind you. Stay out of the parking and off the yards of the houses on Library Place beyond the path. The sun lines up with the wall at 4:12 PM EST on Friday and 4:13 PM EST on Saturday, 5.8 and 5.4 degrees up. These are golden days: at the head-on moment the sun is up to 6 degrees up. The sun reaches 22 m of the 34 m. A house at 95 Library Place rises toward the sun. OpenStreetMap has no height for it, and with an estimated height its roofline is at 1.4 degrees, below the sun on both days. Computed from the building outline and the sun's position, and not checked on the ground.

A building on Monument Drive, a short walk from the Battle Monument. The outline in OpenStreetMap has no name, and the map places the Suzanne Patterson Center at it. A 2026 voting guide lists the center at 1 Monument Drive as a polling place (Princeton University).

Map of The Suzanne Patterson Center on Monument Drive in Henge Days, with the west-southwest wall highlighted and every wall labeled with its bearing — The building page in Henge Days. The highlighted walls face 243°, toward the sunset on the days in the row below; every wall carries its bearing.

Fri, Nov 6 to Mon, Nov 23, 202618 evenings · best Mon, Nov 23

4:34 PM Golden sunset, sun 0° up WSW 243° wall

Its row in the Henge days list, with the time of the head-on moment on the best day. Save keeps that day in your planner, which can send it to your calendar app. Saving asks you to sign in with an email link; there is no password.

A year of head-on days for each wall of The Suzanne Patterson Center on Monument Drive — The year for every wall of the building. Each row is a wall; the colored runs are its henge, golden and low-sun days.

Open this wall in Henge Days

Low sun

These campus walls pass the check for other buildings with the sun 6 to 10 degrees up at the head-on moment. That is higher than golden light, and the light is still warm and falls square on the wall. All of them are evening walls, between 3:46 and 4:03 PM EST, so they fit before the golden walls above. Each name opens the wall in Henge Days.

Blair Hall, the hall of Blair Arch: its west wall, 33 m, faces 241 degrees toward University Place. It gets the sun 6 to 10 degrees up at its moment: 4:02 PM EST on Friday and 4:03 PM on Saturday, 7.5 and 7.1 degrees up. The whole 33 m is lit. A university building at 27 University Place has no height in OpenStreetMap, and with an estimated height its roofline is at 3.8 degrees, below the sun on both days. Stand at the foot of the Blair Arch steps or on the University Place sidewalk, and stay out of the street. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Joline Hall, next to Blair Hall: its west wall, 44 m, faces 241 degrees. It gets the sun 6 to 10 degrees up at its moment: 4:01 PM EST on Friday and 4:02 PM on Saturday, 7.7 and 7.2 degrees up. The sun reaches 16 m of the 44 m. Stand on the campus walks or the University Place sidewalk west-southwest of the hall, and stay out of the street. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Henry Hall, a residence hall at the west edge of the campus: its west wall, 50 m, faces 240 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:56 PM EST on Friday and 3:57 PM on Saturday, 8.4 and 8.0 degrees up. The sun reaches 31 m of the 50 m. Stand on the campus walks west-southwest of the hall, and stay out of Alexander Street and University Place. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Dickinson Hall, next to the Chapel: its west wall, 47 m, faces 239 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:48 PM EST on Friday and 3:49 PM on Saturday, 9.8 and 9.4 degrees up. The sun reaches 41 m of the 47 m. Stand on the campus walks west-southwest of the hall. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
1879 Hall, the arched hall on Washington Road: its west wall, 75 m, faces 238 degrees. It gets the sun under 10 degrees up only on Saturday, at 3:46 PM EST, 9.8 degrees up. The whole 75 m is lit. Woolworth Hall has no height in OpenStreetMap, and with an estimated height its roofline is at 8.2 degrees, below the sun. Stand on the campus walks west-southwest of the hall. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Frist Campus Center, the student center: its west wall, 68 m, faces 239 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:50 PM EST on Friday and 3:51 PM on Saturday, 9.5 and 9.1 degrees up. The sun reaches 41 m of the 68 m. Stand on the campus walks west-southwest of the building, and stay out of any service drive. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Wu Hall, the dining hall of Butler College: its west wall, 43 m, faces 239 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:49 PM EST on Friday and 3:51 PM on Saturday, 9.5 and 9.1 degrees up. The whole 43 m is lit. Stand on the campus walks west-southwest of the hall. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Forbes College, the residential college southwest of the main campus: its west wall, 125 m, faces 240 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:53 PM EST on Friday and 3:54 PM on Saturday, 9.0 and 8.6 degrees up. The sun reaches 122 m of the 125 m, the longest lit wall in this guide. Stand on the college's own walks and lawns west-southwest of the building, and stay off any drive and any private grounds beyond the campus. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Jadwin Hall, the physics building on Washington Road: its west wall, 100 m, faces 240 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:52 PM EST on Friday and 3:53 PM on Saturday, 9.1 and 8.7 degrees up. The sun reaches 84 m of the 100 m. The Carl Icahn Laboratory rises toward the sun to 4.2 degrees, below the sun on both days. Stand on the far sidewalk of Washington Road, west-southwest of the wall, and stay out of the road. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.
Frick Chemistry Laboratory, the chemistry building on Washington Road: its west wall, 129 m, faces 239 degrees. It gets the sun 6 to 10 degrees up at its moment: 3:51 PM EST on Friday and 3:52 PM on Saturday, 9.3 and 8.9 degrees up. The whole 129 m is lit. A university building toward the sun rises to 6.1 degrees, below the sun on both days. Stand on the far sidewalk of Washington Road, west-southwest of the wall, and stay out of the road. Computed from the building outline and the sun's position for a level horizon, and not checked on the ground.

How the list was made

Henge Days computed every named building with a wall of 8 m or more, and every unnamed building with a wall of 20 m or more, within 300 to 400 meters of 13 points. On the campus: Nassau Hall and the front campus, Blair Arch with Rockefeller and Mathey Colleges, the Chapel with Firestone Library and the Art Museum, McCosh Hall and Frist Campus Center, Whitman and Butler Colleges, Yeh College and New College West, the Lewis Center for the Arts, the Graduate College and Cleveland Tower, and Prospect Avenue. In town: Palmer Square and the west end of Nassau Street, Witherspoon Street and Hinds Plaza, the Battle Monument and Stockton Street, and the east end of Nassau Street. It used OpenStreetMap outlines. It kept walls where the sun lines up with the wall within 10 degrees of the horizon on Friday, November 6, or Saturday, November 7. It then traced the sun's path from each wall and dropped the walls where a neighboring building stands higher than the sun. For each wall kept, a second search 400 m out along the sun's path checked for a building beyond the first search. That check dropped no wall.

Two days in early November is a short window. This weekend the head-on sun stands at about 114 degrees in the morning and 245 degrees in the evening. Nassau Hall, Whig and Clio Halls, McCosh Hall, Firestone Library, the Art Museum, Nassau Presbyterian Church and the Princeton Public Library have no wall the sun lines up with on these days. Holder Hall, Alexander Hall on the front campus, the Old Graduate College below Cleveland Tower, Morven Museum and the shop fronts of Nassau Street and Palmer Square line up at sunset, but a taller building stands toward the sun at that moment. That leaves four picks, three on the campus and one in town.

Some walls that line up are left out by the rules for where to stand. A group of unnamed buildings off Bayard Lane by Stanworth Lane lines up at sunset. They read as housing in the map, with the houses of Cleveland Lane beside them, and the only place to stand is their own grounds. The Peacock Inn at 20 Bayard Lane lines up at 4:20 and 4:21 PM EST, but its west side faces the inn's own drive and lot. Palmer House Cottage, by the University's Palmer House on Bayard Lane, lines up at 4:15 and 4:16 PM EST, but its west side faces a lawn the map does not show as public. In the low-sun group, Alexander Hall, Brown Hall and Miller Chapel of Princeton Theological Seminary pass the check, but they are outside the University campus and their walls face the Seminary's own grounds. Albert Einstein's house on Mercer Street lines up in low sun, and it is a private home.

Hills and trees are not part of that check, and the times assume a level horizon. The campus has many tall trees, and in early November some still carry leaves, so a tree between a wall and the low sun can take the light for some minutes. Where an outline has no height, the check assumed one by building type and the entry says so. Every date and time comes from the Henge Days engine, for the building outlines in OpenStreetMap.

How to read each entry

Each entry shows the building as Henge Days shows it. The map marks the building's outline from OpenStreetMap, gives every wall its compass bearing, and highlights the wall that lines up with the sun. Below it are the wall's row from the building's Henge days list, with a Save button that keeps the best day in your planner, and a year of head-on days for every wall. The times on the map labels are for the day the picture was made, October 17, in Eastern Daylight Time.

Any building has a page like the ones above, your student's hall included. Whatever you shoot, post it with #HengeDays.

Find a wall in Henge Days Open your planner

Sources

Features

What Henge Days does, part by part, with a live example for each. Everything runs from a building's real outline and the sun's computed position.

Henge days for any building

Type an address or a landmark. Henge Days finds the building's outline in OpenStreetMap, gives every wall a compass bearing, and works out when the sun's bearing matches it. The Henge days tab lists every window for the next 12 or 24 months in date order: henge days with the sun on the horizon, golden light under 6°, low sun under 15°. Filters pick the tiers and sunrise or sunset. Each row has the best day, the time, a calendar event and a Save button.

Virginia Museum of Fine Arts, Richmond · Flatiron Building, New York

Today

The Today tab shows the chosen day for the selected wall: a timeline of when the sun strikes it and how squarely, the head-on minute, and the week ahead. The day can be any day you choose. A cloud forecast from Open-Meteo sits beside each day within 10 days.

The museum today

Along a street

Two ends of one street, the street's name or route number, and a day. Henge Days stitches the street's OpenStreetMap ways into one path, keeps the walls within 60 m that face the road, and lists the ones the sun reaches that day in the order you pass them. Each stop has the distance from the first end, the side of the road, the time the sun is square to the wall or at its best angle, the tier, and the wall. The map draws the street and marks each lit wall. A plan covers up to 5 km of one street.

US 17 through Tappahannock, December 12 · Main Street, Mathews, October 24 · Arthur Ashe Boulevard, Richmond, November 17

Planner

Sign in with an email link to save buildings and days. The planner keeps an agenda of your saved days in date order, with a countdown, the cloud forecast, and a note for each. The shot card for a day gives a stand point 1.5 wall lengths back from the wall, links to open it in Apple Maps or Google Maps, an arrive-by time, and a Shot or Missed mark afterwards. The agenda also lists days coming up at your saved buildings that you have not saved yet.

Open the planner

Calendar feed and calendar files

Any row downloads a calendar event with the stand point in its location. The planner also offers a private calendar feed: subscribe once in Apple Calendar, Google Calendar or Outlook and every saved day appears and stays current. The feed link can be rotated at any time.

Henge pages

A set of pages, one per building or street, with every head-on date and time for the year ahead written out on the page, computed when the site is built. They are for reading, for search engines and for AI assistants, and each has a Markdown form and a JSON file. The buildings and streets on the site's examples are there to start.

Henge pages

The Share button copies a link to the building, the selected wall and the map view. Pasted into a message or a post, the link shows the building's name and its next henge day, or the wall and date of the row you selected.

A link to one row at the museum

Open data and accuracy

Building outlines come from OpenStreetMap. Addresses are looked up with Nominatim, Photon and the US Census Bureau geocoder. Sun positions come from the NOAA solar position algorithm, computed in your browser for every day in the range. Cloud forecasts come from Open-Meteo. None of the dates are checked on the ground: hills, trees, other buildings and weather are not included, so treat each one as a plan to confirm before you travel. Terms and accuracy has the detail.

The day the sun hits that wall head-on.

Light you can put in the calendar

Find a wall's days

Drive a street for the light

Plan the shot

Flatiron Building

Live right now

Three streets, live

Church Lane, Tappahannock, VA

Main Street, Mathews, VA

North Arthur Ashe Boulevard, Richmond, VA

What is a henge day?

How it works

Privacy

What is recorded

If you sign in

What is not recorded

How long it is kept

Questions

Terms and accuracy

What the dates are

What is not included

No warranty

Your responsibility

Liability

Changes to the service

Map and address data

Acceptable use

Questions

Admin Dashboard

Planner

Release notes

Princeton First-Year Families Weekend, November 6 and 7, 2026: four buildings to photograph on campus and in the town of Princeton

The weekend's schedule

Part 1: the campus

1 Princeton University Chapel

2 Princeton Stadium

3 The five-story university building on Woodland Way

Part 2: the town of Princeton

4 The Suzanne Patterson Center on Monument Drive

Low sun

How the list was made

How to read each entry

Sources

Features

Henge days for any building

Today

Along a street

Planner

Calendar feed and calendar files

Henge pages

Share links

Open data and accuracy