What is a solargraph or solar pinhole camera?

A solargraph is a long-exposure pinhole camera — often a film can — that records the sun's path across the sky over days or weeks. This simulator shows the trail before you drill the hole or mount the can.

Can I simulate a solargraph in Guyana?

Yes. Defaults include Georgetown and other Guyana coordinates. Near the equator, sun paths are steep year-round; the simulator uses accurate ephemeris for your aim direction and exposure length.

How long should a solargraph exposure be?

Many makers run days to months. Longer exposures thicken the daily arcs and include more seasons. Preview different day counts here before committing paper and a can outdoors.

Tools

Free Solar Pinhole Camera Simulator

Aim a virtual can at the sky, set exposure days, and preview the sun trail burned onto paper — accurate to your latitude and aim.

Tap a section to expand settings

Focal length (f)Inner radius

⚠ Nominal — measure before building.

Diameter (∂)Wall (w)

Glossy emulsion faces the pinhole; enable Mirror for correct left↔right on the paper.

Mirror (emulsion / glossy side)Negative (paper)

Sky background

Can model

LatitudeLongitude

Start dateExposure days — 7

Step (min)Horizon cutoff (°)

Atmospheric refractionCloudy weather (broken / faded trails)

15°

30°

45°

60°

75°

paper FOV

pinhole / bore

paper FOVθ_vigboreDrag · pinch zoom
TrailsStartMidEnd

Bore azimuth90°

Bore altitude0° above horizonMid-height pinhole · bore normal to curved wall

Simulated paper

Cylindrical projection — paper wrapped on the inner wall, pinhole at mid-height (procedural sky). When the bore is tilted upward the horizon appears as a gentle curve near the lower edge. Trail brightness follows cos⁴θ falloff, airmass extinction, and soft bore vignetting. Shown inverted as the paper records it. 143 of 532 sun samples land on the 178 × 127 mm paper.

Optics

Slant f (pinhole→base): 85.0 mm; Blur reference on flat geometry
Preview scale (2R): 65.8 mm; Cylindrical paper at bore
Effective f: 85.0 mm; f − wall/2
f-number: f/177
Optimal pinhole (slant): 0.411 mm; 1.9·√(λf_eff)
Optimal pinhole (2R): 0.361 mm; For paper preview scale
Trail width (preview): 0.61 mm; max(sun disk, blur) at 2R
Sun disk (2R preview): 0.61 mm; 2R·0.53°
Capture width: ±77°; Azimuth (cylindrical)
Capture height: ±44°; Altitude at bore centre
Vignetting limit: 90°; θ_vig = atan(∂/w)

Pinhole size is close to optimal for the cylindrical preview scale.

The can stands upright on its flat base. The pinhole is at the centre of the curved wall (mid-height); compass and tilt aim the bore. Paper wraps the inner wall (cylindrical projection). f is the slant distance pinhole→base centre for blur calculations. Measure your container. Presets are nominal.

Real paper results

Solargraphy lesson

Frequently asked questions

What is a solargraph or solar pinhole camera?: A solargraph is a long-exposure pinhole camera — often a film can — that records the sun's path across the sky over days or weeks. This simulator shows the trail before you drill the hole or mount the can.
Can I simulate a solargraph in Guyana?: Yes. Defaults include Georgetown and other Guyana coordinates. Near the equator, sun paths are steep year-round; the simulator uses accurate ephemeris for your aim direction and exposure length.
How long should a solargraph exposure be?: Many makers run days to months. Longer exposures thicken the daily arcs and include more seasons. Preview different day counts here before committing paper and a can outdoors.

Plan a solargraph build with physics-based sun trails, field of view, and blur — then pair it with the Pinhole Optics Calculator for hole size and focal geometry.

Free Solar Pinhole Camera Simulator

Container

Pinhole

Paper

3D preview

Location

Exposure

Simulated paper

Optics

Real paper results