Sextant Pro

Celestial navigation

$9.99 · Designed for iPad. Not verified for macOS.

Now on Mac: AR sextant, Sky Tonight star chart, GPX/KML chart overlays, and a multi-day Hawaiian Passage demo — all offline, all from the published almanac. Sextant is a modern celestial-navigation logbook and sight-reduction calculator for sailors, students, and anyone who wants to know where they are without a GPS. Enter a sight — the body, the precise UTC time of the mark, your sextant altitude, your height of eye — and Sextant does the rest: almanac lookup, altitude corrections (dip, refraction, semi-diameter, parallax), intercept-method reduction, and an on-screen plotting sheet you can read like the paper original. What's in 1.2.0: • Mac Catalyst — same app, native on Apple silicon Macs. • AR sextant — line up the body in your camera and the device records the altitude (calibrate against a known horizon first). • Chart overlays — import GPX or KML route/waypoint files and they render directly on the plot sheet. • Sky Tonight — table of every body above your horizon right now, plus a "Chart" view showing star positions on a stereographic dome. • GPS-default observer — Sky Tonight, noon-run setup, and the AR HUD all start from your current GPS fix (still optional; the manual DR workflow is unchanged). • Demo voyage — tap "Try a sample voyage" for a 3-day Hawaiian Passage with five Sun sights, two noon runs, three Polaris obs, and three computed fixes. • Localized in French, Spanish, German, and Norwegian Bokmål (body names and nav abbreviations stay in their nautical-standard form). The fundamentals haven't changed: • Sun, Moon, Venus, Mars, Jupiter, Saturn, and 57 Nautical-Almanac stars. • Fully offline forever. The ephemeris is computed from Meeus, VSOP87, and ELP-2000 algorithms — there are no almanac files to update, no annual app refresh. • Sync across iPhone, iPad, Mac, and Apple Watch via your private iCloud database. • Apple Watch companion: one-tap MARK captures the exact moment of a sight, then sync to your phone to finish the entry. • Built on the published Nautical Almanac — every algorithm is graded against JPL Horizons values to arc-minute precision. • No tracking. No advertising. No third-party SDKs. Nothing leaves your iCloud account. Built for navigators who want the dignity of the math, not the seduction of a black box.

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The developer, Will Arentz, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

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    Information

    Seller
    • Will Arentz
    Size
    • 3.5 MB
    Category
    • Reference
    Compatibility
    Requires iOS 18.0 or later.
    • iPhone
      Requires iOS 18.0 or later.
    • iPad
      Requires iPadOS 18.0 or later.
    • Mac
      Requires macOS 15.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 2.0 or later.
    Languages
    English and 4 more
    • English, French, German, Norwegian Bokmål, Spanish
    Age Rating
    4+
    Copyright
    • © Ergodics AS
  • Privacy Policy

    • Supports

    • Family Sharing

      Up to six family members can use this app with Family Sharing enabled.

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