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 Willets Hall at Swarthmore College in Henge Days, with its east-southeast wall highlighted in pink and every wall labeled with its bearing. — Willets Hall, the longest wall in the list and the family photo spot, in Henge Days. Pink marks the wall the morning sun lines up with on both days of Garnet Weekend.

Swarthmore College Garnet Weekend, October 30 and 31, 2026: four morning walls and one afternoon wall to photograph on campus, and the light in the Ville between events

Swarthmore College Garnet Weekend, October 30 and 31, 2026: four campus walls that line up with the low morning sun, when to be there around the weekend's events, where to stand for the family picture, a wall in low afternoon light, and the light in the Ville between events.

For October 30 to 31, 2026.

Garnet Weekend, Swarthmore College's homecoming and family weekend, runs on Friday, October 30, and Saturday, October 31, 2026. This guide lists four walls on campus that the low morning sun lands on square that weekend, and one that gets low afternoon sun. It gives the times and a spot for the family picture. It adds where the light falls in the Ville, the small downtown at the foot of Magill Walk, between events. Post yours with #HengeDays.

Every time in this guide is US Eastern (Eastern Daylight Time). For a level horizon, the sun rises at 7:28 AM on Friday and 7:29 AM on Saturday, at about 108 degrees, and sets at 6:01 and 6:00 PM, at about 252 degrees. Four walls on campus have a clear view of the sun this weekend, all of them in the morning. No wall in the Ville passes the checks.

The weekend's schedule and the light

The College's Garnet Weekend page gave October 30 and 31, 2026, as the dates in search results on October 17, and called the weekend its homecoming and family weekend. Those results held no 2026 list of events, and the registration page could not be opened from where this guide was written. The one event below comes from the College's pages on earlier Garnet Weekends. Swarthmore has had no football team since 2000, so no game is on the list. Check the schedule at swarthmore.edu/garnetweekend and match it to the light below.

Friday, October 30, morning: sunrise is at 7:28 AM. At 7:30 AM the sun lines up with the east-southeast wall of the Benjamin West House, 0.1 degrees up. Dana Hall and Kyle House follow at 7:52 AM and Willets Hall at 8:03 AM.
Friday, October 30, evening: the Garnet Athletics Hall of Fame induction. In recent years it has been held on the Friday evening of Garnet Weekend, in 2025 at the Lang Performing Arts Center (Swarthmore College). The search results gave no 2026 time or place. Before it, Martin Hall's west-southwest wall gets low sun at 5:02 PM. Sunset is at 6:01 PM.
Saturday, October 31, morning: sunrise is at 7:29 AM. Dana Hall lines up at 7:50 AM, Kyle House at 7:51 AM and Willets Hall at 8:02 AM, the family photo spot below.
Saturday, October 31, afternoon: Martin Hall gets low sun at 5:04 PM, and the sun sets at 6:00 PM.

Part 1: The Swarthmore College campus

Four walls, in the order a morning runs, each with a clear view of the sun in the map data. Three are residence halls, seen from campus walks and lawns. The whole campus is the Scott Arboretum. Its trees are not part of the check, and many stand close to these walls.

1 Benjamin West House

Swarthmore College, Swarthmore, Pennsylvania

Wall: east-southeast, facing 108°
Sun: The rising sun lines up with this wall on Oct 30. Best: Friday, October 30 at 7:30 AM, 0.1° above the horizon.
Leaves: The campus is the Scott Arboretum, and its trees stand close to many walls. A forecast issued October 12 put peak color in Philadelphia County, next to Delaware County, around October 26 (More Than Just Parks). Trees in front of a wall can still carry leaves and shade it when the sun is this low.
Where to stand: The wall is the house's east-southeast side. Stand on the campus lawn or the footpath east-southeast of the wall, with the sun behind you. Stay off Visitor's Center Road south of the house. The sun lines up with the wall at 7:30 AM on Friday, 0.1 degrees up, two minutes after sunrise. On Saturday the sun rises already past square to this wall. Nothing in the outlines stands in the way, so the whole 16 m wall is in the sun. Computed from the building outline and the sun's position, and not checked on the ground.
Clear view: Clear. No building in the map data rises above the sun (0.1° up) in its direction.

The house is the birthplace of the painter Benjamin West, born in 1738. It was named a National Historic Landmark in 1965 (Wikipedia). The College uses it for its visitor information center and the offices of Public Safety (Clio).

Map of Benjamin West House 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 108°, toward the sunrise on the days in the row below; every wall carries its bearing.

Tue, Oct 27 to Fri, Oct 30, 20264 mornings · best Fri, Oct 30

7:30 AM Henge sunrise, sun on the horizon ESE 108° 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 Benjamin West House — 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

2 Dana Hall and Hallowell Hall

Swarthmore College, Swarthmore, Pennsylvania

Wall: east-southeast, facing 111°
Sun: The low morning sun lines up with this wall on Oct 30 to 31. Best: Saturday, October 31 at 7:50 AM, 3.3° above the horizon.
Leaves: The campus is the Scott Arboretum, and its trees stand close to many walls. A forecast issued October 12 put peak color in Philadelphia County, next to Delaware County, around October 26 (More Than Just Parks). Trees in front of a wall can still carry leaves and shade it when the sun is this low.
Where to stand: The wall is a short east-southeast side, 11 m long. Stand on the lawn east-southeast of it, inside the loop of Parrish Hall Road, with the sun behind you. Stay off Parrish Hall Road. The sun lines up with the wall at 7:52 AM on Friday and 7:50 AM on Saturday, 3.7 and 3.3 degrees up. These are golden days: at the head-on moment the sun is 2 to 6 degrees up. The Woman's Resource Center stands toward the sun and has no height in OpenStreetMap. With the height the check assumed, its roofline is at 2.6 degrees, below the sun on both days. Computed from the building outline and the sun's position, and not checked on the ground.
Clear view: Clear. No building in the map data rises above the sun (3.3° up) in its direction.

Dana and Hallowell are residence halls on the south side of the campus, both built in 1967. A connector that opened in 2015, known as Danawell, joins them into one building (Swarthmore College).

Map of Dana Hall and Hallowell Hall 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 111°, toward the sunrise on the days in the row below; every wall carries its bearing.

Mon, Oct 26 to Sun, Nov 8, 202614 mornings · best Sun, Nov 8

6:39 AM Golden sunrise, sun 0° up ESE 111° 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 Dana Hall and Hallowell Hall — 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 Kyle House

Swarthmore College, Swarthmore, Pennsylvania

Wall: east-southeast, facing 112°
Sun: The low morning sun lines up with this wall on Oct 30 to 31. Best: Saturday, October 31 at 7:51 AM, 3.4° above the horizon.
Leaves: The campus is the Scott Arboretum, and its trees stand close to many walls. A forecast issued October 12 put peak color in Philadelphia County, next to Delaware County, around October 26 (More Than Just Parks). Trees in front of a wall can still carry leaves and shade it when the sun is this low.
Where to stand: The wall is the hall's east-southeast side, 10 m long. Stand on the lawn a few steps east-southeast of it, with the sun behind you. Stay off the drive that passes the wall, Whittier Place and the grounds of Courtney Smith House, the president's house, farther in the same direction. The sun lines up with the wall at 7:52 AM on Friday and 7:51 AM on Saturday, 3.9 and 3.4 degrees up. These are golden days: at the head-on moment the sun is 2 to 6 degrees up. Courtney Smith House has no height in OpenStreetMap. With the height the check assumed, its roofline is at 2.4 degrees, below the sun on both days. Computed from the building outline and the sun's position, and not checked on the ground.
Clear view: Clear. No building in the map data rises above the sun (3.4° up) in its direction.

Kyle House is a small residence hall at 1 Whittier Place, first occupied in 2003 (Swarthmore College).

Map of Kyle House 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 112°, toward the sunrise on the days in the row below; every wall carries its bearing.

Mon, Oct 26 to Sun, Nov 8, 202614 mornings · best Sun, Nov 8

6:40 AM Golden sunrise, sun 0° up ESE 112° 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 Kyle House — 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

4 Willets Hall

Swarthmore College, Swarthmore, Pennsylvania

Wall: east-southeast, facing 113°
Sun: The low morning sun lines up with this wall on Oct 30 to 31. Best: Saturday, October 31 at 8:02 AM, 5.2° above the horizon.
Leaves: The campus is the Scott Arboretum, and its trees stand close to many walls. A forecast issued October 12 put peak color in Philadelphia County, next to Delaware County, around October 26 (More Than Just Parks). Trees in front of a wall can still carry leaves and shade it when the sun is this low.
Where to stand: The wall is the hall's long east-southeast side, 44 m. Stand on the campus lawn and walks east-southeast of it, with the sun behind you. The sun lines up with the wall at 8:03 AM on Friday and 8:02 AM on Saturday, 5.7 and 5.2 degrees up. These are golden days: at the head-on moment the sun is 2 to 6 degrees up. Bond Lodges and Worth Hall stand toward the sun and have no height in OpenStreetMap. With the height the check assumed, their roofline is at 4.7 degrees, below the sun, and 32 m of the 44 m wall is in the sun on both days. Computed from the building outline and the sun's position, and not checked on the ground.
Clear view: Clear. No building in the map data rises above the sun (5.2° up) in its direction.

Willets Hall is a residence hall in the middle of the campus, home to about 213 students, most of them first-years (Swarthmore College). It was first occupied in 1959 (Swarthmore College).

Map of Willets Hall 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 113°, toward the sunrise on the days in the row below; every wall carries its bearing.

Fri, Oct 30 to Fri, Nov 13, 202615 mornings · best Fri, Nov 13

6:45 AM Golden sunrise, sun 0° up ESE 113° 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 Willets Hall — 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 lawn a few steps out from the east-southeast wall of Willets Hall, turned partway toward the camera. The photographer stands east-southeast of them, with the sun low behind and to one side, which lights faces and the wall behind them in the same warm light. Go on Saturday at 8:02 AM, or on Friday at 8:03 AM, the morning of the Hall of Fame induction. Post it with #HengeDays. Computed from the building outline and the sun's position, and not checked on the ground.

Part 2: The Ville

The Ville is the borough of Swarthmore's small downtown, at the foot of Magill Walk past the SEPTA station, along Dartmouth and Park Avenues. No wall in the Ville passes the checks this weekend. The long west-southwest side of the Swarthmore Co-op, the borough's grocery store on Dartmouth Avenue, lines up with the sunset at 5:55 PM on Friday and 5:56 PM on Saturday, 0.7 and 0.3 degrees up. The Inn at Swarthmore stands toward the sun and has no height in OpenStreetMap. With the height the check assumed, its roofline is at 1.7 degrees, above the sun, so the wall may be in its shadow. The ground in front of that wall is Dartmouth Court and a parking area, with no sidewalk in the map data, so the Co-op is not an entry.

For a picture in the Ville, walk down Magill Walk from Parrish Hall to the station in the late afternoon. At 5:00 PM on both days the sun is about 10 degrees up at 242 degrees, west-southwest, and at 5:30 PM it is about 5 degrees up at 247 degrees. Those times come from the sun's position alone. Trees and buildings west of the Ville are not part of them.

Low sun

With few walls in golden light, this wall gets the low afternoon sun square on. At the head-on moment the sun is 6 to 10 degrees up, higher than in golden light, so the color is less warm and the shadows are shorter.

5 Martin Hall

Swarthmore College, Swarthmore, Pennsylvania

Wall: west-southwest, facing 242°
Sun: The evening sun lines up with this wall, 6 to 10° up, on Oct 30 to 31. Best: Saturday, October 31 at 5:04 PM, 9.2° above the horizon.
Leaves: The campus is the Scott Arboretum, and its trees stand close to many walls. A forecast issued October 12 put peak color in Philadelphia County, next to Delaware County, around October 26 (More Than Just Parks). Trees in front of a wall can still carry leaves and shade it when the sun is this low.
Where to stand: The wall is the west-southwest side, 27 m. The wall comes in two parts, either side of a corner. Stand on the campus lawn between the wall and Whittier Place, west-southwest of it, with the sun behind you. Stay out of Whittier Place. OpenStreetMap marks the building as under construction. If a fence is up, stay outside it. The sun lines up with the wall at 5:02 PM on Friday and 5:04 PM on Saturday, 9.6 and 9.2 degrees up. This is low sun: at the head-on moment the sun is 6 to 10 degrees up. Nothing in the outlines rises above the sun, and 23 m of the 27 m wall is in the sun on both days. Computed from the building outline and the sun's position, and not checked on the ground.
Clear view: Clear. No building in the map data rises above the sun (9.2° up) in its direction.

Martin Hall opened in 1937 as the College's biology building (The Phoenix). Its renovation turns it into a home for the Film and Media Studies and Computer Science departments (Goody Clancy).

Map of Martin Hall 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 242°, toward the sunset on the days in the row below; every wall carries its bearing.

Mon, Oct 19 to Thu, Nov 26, 202639 evenings · best Thu, Nov 26

4:37 PM Low sun sunset, sun 0° up WSW 242° 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 Martin Hall — 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

How the list was made

Henge Days computed every building within 300 to 400 meters of 11 points: Parrish Hall and Parrish Beach, the Science Center and the Friends Meeting House, McCabe Library and Kohlberg Hall, the Lang Performing Arts Center and Clothier Hall, Sharples and Wharton Hall, the Lamb-Miller Field House and Clothier Field, Magill Walk and the station, the Ville, the Presbyterian Church and Borough Hall, and two points on State Street in Media, about 4 km northwest. It used 784 OpenStreetMap outlines. It kept named buildings with a wall of 8 m or more, and unnamed ones with a wall of 20 m or more, where the sun lines up with the wall within 10 degrees of the horizon on October 30 or 31.

It then traced the sun's path from points along each wall over all 784 outlines and dropped walls where a neighboring building stands higher than the sun. Almost no outline on the campus or in the Ville carries a height, so the check estimated heights by building type. Two days is a short window, and the checks leave four clear walls, all on campus, fewer than in this package's other guides. The other walls that line up stand behind a neighbor or fail the access rule below, so the list has four picks and one wall in low sun.

Courtney Smith House, the president's house, has a wall that lines up with a clear view. ABC House on Harvard Avenue also lines up in the scout's first pass. Each is a home, so neither is on the list. Three walls are blocked only by a building with an estimated height, and each lacks a public place to stand. The Swarthmore Co-op is described under Part 2. Woolman Hall lines up at 7:30 AM on Friday, but an unnamed college building in front of it rises to an estimated 1.9 degrees, and the wall faces houses off Walnut Lane with no campus walk in front. The Swarthmore Presbyterian Church gets low sun at 5:17 and 5:18 PM, but ABC House rises to an estimated 9.9 degrees in front of it, and the ground in front of the wall is the church's drive and the neighboring lot. Whittier Hall, the Lang Center for Civic and Social Responsibility, the Palmer, Pittenger and Roberts residence halls and the east wall of the field house stand behind neighbors well above the sun. Two unnamed college buildings near Whittier Place line up but are shaded. In Media, two State Street walls line up, but one is shaded and the other has 7 m of its 21 m wall in the sun, too little to photograph. Parrish Hall, Clothier Hall, McCabe Library and the Lang Performing Arts Center have no wall the sun lines up with on these days.

Hills and trees are not part of that check, and the times assume a level horizon. The Scott Arboretum's trees cover the campus and can shade a wall when the sun is this low, and the Crum Creek valley drops away west of the campus. Each entry names the building that rises highest toward the sun from in front of the wall. Where its outline carries no height, the check assumed one and the entry says so. Every date and time comes from the Henge Days engine for the wall's own bearing.

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.

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

Swarthmore College Garnet Weekend, October 30 and 31, 2026: four morning walls and one afternoon wall to photograph on campus, and the light in the Ville between events

The weekend's schedule and the light

Part 1: The Swarthmore College campus

1 Benjamin West House

2 Dana Hall and Hallowell Hall

3 Kyle House

4 Willets Hall

Part 2: The Ville

Low sun

5 Martin Hall

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