Lodestar

Aim your camera at the night sky.

Project maintained by feetball Hosted on GitHub Pages — Theme by mattgraham

Support

Getting started

  1. Mount your iPhone rigidly on the camera (a hot-shoe or tripod phone mount works) and choose that mount in Settings ▸ Mount. Enter your camera’s sensor and lens in Settings ▸ Camera & Lens.
  2. Allow location access (approximate is fine) or choose an observing site on the map.
  3. Align on a bright star or planet: centre it in your camera’s viewfinder or live view and tap Sync. For best results, align on a star near your target, or add a second star far from the first.
  4. Pick a target and follow the arrows until Lodestar says it is in your frame, then fine-tune in your camera’s live view.

Frequently asked questions

How accurate is it? Sky positions are computed to arcseconds. The limit is the phone’s compass, which camera bodies and metal tripods can disturb by several degrees. Star alignment removes most of that error, and Gyro Lock (Settings ▸ Mount) keeps the compass out of it afterwards.

The arrows seem wrong. Check Settings ▸ About ▸ Sensor Diagnostics: with the phone upright and the camera facing north, the gravity check should read PASS. Make sure the mount setting matches how the phone sits on the camera, then align on a star.

How do I make the whole screen red? Lodestar’s night mode is red, but some system elements (keyboard, menus) cannot be tinted by apps. For a fully red screen, set up iOS Color Filters (Settings ▸ Accessibility ▸ Display & Text Size ▸ Color Filters ▸ Color Tint, intensity and hue at maximum) and assign it to the Accessibility Shortcut (triple-click the side button).

Does it need an internet connection? No. Only the site map and the time-zone lookup for a new site use the network.

Contact

Report a problem or ask a question on the issue tracker: https://github.com/feetball/Lodestar/issues.

Credits

Star data: HYG Database v4.1 (CC BY-SA 4.0). Deep-sky data: OpenNGC (CC BY-SA 4.0). Constellation figures and Milky Way outlines: d3-celestial (BSD-3-Clause). Geomagnetic model: NOAA/BGS WMM2025.