The sun rises at a different bearing every morning of the year, farthest north in June and farthest south in December. This page draws that sweep on the view from a photo spot: the spot's reference frame, unrolled so that compass bearing runs left to right, with one marker per logged morning at the bearing of sunrise that day and, where the frame shows it, the sun the sweep found. Nothing is drawn by hand. Every marker is measured, the calibration comes from the sun itself, and a sentence appears only when it rests on at least 5 mornings.
Cherokee Trail, Stone Mountain
The Indian Island dock
The wooden dock on the east shore of Indian Island, facing east across Stone Mountain Lake. Position is the mean of the phone's GPS tags on the photographs taken from it. About 60 m from the shore spot, far enough that the two share no reference.
Hover or tab across the markers for the date, the sunrise bearing and the observed sun. Each marker opens that morning. One row per year, 2024 at the top.
- Sunrise bearing, one marker per morning: the morning's sky color where a photograph exists, outlined where not
- The glow the sweep found above the treeline, with a tick to its computed marker
- The sun's disk where it was in the frame
Across 118 mornings at the Indian Island dock, the sun rose between 61 degrees on June 22, 2025 and 118 degrees on December 22, 2024, a span of 57 degrees.
Across 11 mornings with the sun found in the frame, the observed bearing sat a median of 4.6 degrees from the computed one. The calibration comes from the sun itself, so that number is spread, not absolute error.
Method
Each photograph taken at the spot is registered to the reference frame by the shape of its treeline against the sky, a rotation-only camera model with the focal length from the EXIF equivalent; point features do not survive the seasons on a silhouetted far shore. The strip is the reference frame unrolled onto a cylinder, so bearing is linear in x. The sun almost never shows as a disk here (it is below the treeline or behind cloud when the frame is taken), so the sweep reads the glow, the brightest column just above the treeline, and a glow counts only when the ephemeris puts the sun inside the frame. The calibration fixes the heading from those glows at their capture times: bearing = a times x plus b, where a is the strip's own geometry (glows (heading only)). Without four true disks the strip is not leveled, so the markers sit on the median treeline row rather than a horizon. Because the calibration comes from the sun itself, a residual (observed minus computed at the capture clock) measures spread, where the photographer stood, the clock, cloud moving the glow and the detection, not absolute error. The sanity gate this spot passed asks that a free fit of bearing against strip column match the geometry within 20 percent over at least six detections spanning 30 degrees. A terrain check against the elevation model (tools/hikealong/sweep_dem.py) is run by hand and reported, never typed onto this page; the methods page says what the residual does and does not mean.
Cherokee Trail, Stone Mountain The sunrises wall The almanac How the sweep is measured