star-trails
Stack timelapse photos or a video into one star trail image. Photo exports preserve the EXIF from the first frame.
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Look
Frames 1 of 84
Fade Curve fades along a curve you set with the decay slider: a low decay keeps older frames bright for an even trail, a high one drops them off fast for a bright head with a faint tail.
Linear steps down by the same amount across the frames you selected, so the oldest is the faintest. Widen the range for longer trails.
Linear steps down by the same amount across the frames you selected, so the oldest is the faintest. Widen the range for longer trails.
Curve
Linear
Min opacity 0%
Rotation 0°
Export
Format
Image
Video
Live Photo
1080 × 1620 JPEG, full resolution, quality 95. Full size is slower because every frame is decoded again.
How does it work?
Every frame uses a lighten blend, keeping the brightest pixel at each position. The stars move between frames, drawing trails while the landscape stays still.
Curve makes trails longer as you select more frames. Higher decay makes the bright end of each trail sharper. Linear keeps the trail length fixed, even when you select more frames. Min opacity keeps older frames visible.
Shooting for it
Use 20 to 40 second exposures with the shortest gap possible. Shoot on a tripod and lock focus and exposure. More frames give you more room to adjust the range later.
Your photos stay on your computer
Everything runs in your browser. Nothing is uploaded, and your photos and videos never leave your computer. There is also a command line version for processing a folder from the terminal.
Made by Javier Bórquez.