On-device · Offline · Private

Firmament

Point your iPhone at the real sky and understand it.
Then capture it.

◎ Install on iPhoneTestFlight — coming soon ⌥ Build it yourselfOpen source on GitHub

No public download link exists on iOS by design — Apple ships betas through TestFlight. Until then, clone & run it on your own device in minutes.

What it does

Explore live

Hold the phone up: stars, planets, the Sun & Moon (with phase) and constellations label themselves, anchored to their true direction in your sky, right now. Tap for the facts.

Spot roadmap

Arrows guide you to where the ISS and bright satellites are passing overhead, with a live countdown to the next visible pass.

Capture tripod

Set it down and Firmament detects it's steady, then pushes the camera to its limit — long exposure, RAW frame-stacking, night-mode assist — behind one clean shutter.

Real sky, honestly computed

From your place & time

CoreLocation gives place + true heading; CoreMotion gives where the phone points and whether it's steady.

Meeus & JPL math

Sun, Moon (with phase), and the naked-eye planets from standard ephemeris; a bundled bright-star catalog. Naked-eye pointing grade.

Nothing invented

Where a value is approximate, the app says so. Real over invented; reverence over spectacle — the same philosophy as the Universe Engine.

Install on your own iPhone (5 minutes, free Apple ID)

  1. brew install xcodegen
  2. git clone https://github.com/sinhaankur/Firmament.git && cd Firmament
  3. xcodegen generate && open Firmament.xcodeproj
  4. In Xcode → Signing & Capabilities, choose your Team.
  5. Plug in your iPhone, select it, press ⌘R.

Platforms

iOS · soon iPhone 17 Pro & iOS 17+ LiDAR foreground occlusion + Pro cameras on the reference device; graceful fallback elsewhere. TestFlight link lands here.
Android · planned ARCore + CameraX A separate native app built against the same spec. Tracked in the repo's android/ slot — honest roadmap, not a shipped claim.