How to use a star tracker for night-sky photography

Earth's rotation makes stars move across a fixed camera's frame. A tracker turns the camera to compensate for that motion. If the mount is aligned and running correctly, a longer exposure can record stars with less trailing than a stationary camera at the same focal length. It does not remove cloud, skyglow, focus errors or vibration. NASA's astrophotography guide explains the role of a tracking drive.

A tracker is optional for a first night-sky photo. A fixed tripod is simpler for learning focus and framing; tracking is useful when you want to experiment with longer exposures and are willing to spend time setting up. A tracked sky and a stationary foreground move relative to each other, so a long tracked landscape exposure can blur the ground.

1. Choose a safe location with permission to be there at night. Check weather and keep clear of traffic and unstable edges.
2. Set the tripod on firm ground and secure the tracker, camera and lens. Follow the tracker manual for mounting, balance, compatible load and any counterweight. Check that cables cannot snag as the mount moves.
3. Check power, memory space and the correct tracking mode for the device. Choose the appropriate hemisphere or direction if the tracker requires it.
4. Point the tracker's polar axis toward the relevant celestial pole, then follow its alignment procedure. The Sky-Watcher Star Adventurer manual is one example; controls and alignment methods differ between models.

In the Northern Hemisphere, Polaris is near the north celestial pole, but it is not exactly on it. A polar scope or alignment app may show where Polaris belongs in the reticle for your location and time. Do not simply centre Polaris and assume alignment is complete.

In the Southern Hemisphere, the south celestial pole has no comparably bright nearby pole star. Depending on the mount and your view of the sky, alignment may use a polar scope with southern reference stars or a supported camera-assisted method. Follow the instructions for your own hardware; an app or accessory does not replace checking the result. Sky-Watcher's mini manual describes its northern and southern procedures.

Avoid disturbing the tripod or alignment adjustments after aligning. If you move them, check alignment again. Never look at the Sun through an unfiltered polar scope, camera lens or telescope.

Frame a bright star field, focus carefully and take a short test image. Magnify the image to inspect stars across the frame. Then try a longer exposure and compare it with the first. Use the camera's timer or a remote release if pressing the shutter shakes the setup. NASA's camera and phone guidance covers steady support and locked focus.

There is no reliable universal shutter speed or ISO for a tracker. Focal length, alignment, mount behavior, wind, sky brightness and the camera all affect the result. If stars trail, shorten the exposure and investigate. If the sky or stars are clipped, reduce exposure or adjust the camera settings; inspect the histogram and the image rather than targeting one fixed histogram position.

• Stars trail in the same direction: check that tracking is running in the correct mode and hemisphere, then recheck polar alignment and tripod movement.
• Stars look soft or uneven: inspect focus, lens performance and vibration as well as tracking. A badly focused frame can look poor even when the mount is moving correctly.
• The foreground is blurred: make a separate stationary foreground exposure if you intend to combine it with the tracked sky; keep the original files.
• Frames worsen over time: check power, cable snagging and whether the mount is approaching a physical limit. Use your device's instructions before changing its setup.

Once several test frames look acceptable, record a series and review it for rejects. Stacking can help combine suitable frames, but it cannot turn every blurred exposure into a sharp one. Our processing guide covers sorting and stacking.

Reviewed 14 November 2026 using NASA's astrophotography guide, NASA's smartphone guidance and Sky-Watcher's Star Adventurer and mini manuals. Device-specific steps and limits may differ; use the manual supplied with your equipment.