Mobile Observatory Astronomy

Wolfgang Zima

In-app purchases

About this app

Mobile Observatory: The Only Astronomy App with Real Horizon Data

See exactly when celestial objects rise above YOUR hills and mountains. Mobile Observatory computes your actual local horizon using NASA topographic data - a feature no other astronomy app offers. Know precisely when the Moon clears that ridge or when Saturn becomes visible above the treeline.

NEVER MISS A CELESTIAL EVENT
Get push notifications for:
- Aurora alerts when Kp-index spikes at your location
- Solar flare alerts from GOES satellite X-ray data
- ISS pass reminders with brightness and trajectory predictions
- Daily celestial events including conjunctions, eclipses, and meteor showers
- Custom event reminders via calendar integration

REAL TOPOGRAPHIC HORIZON - AN ASTRONOMY APP FIRST
Download NASA SRTM elevation data for your location and see the true profile of mountains, hills, and ridges blocking your view. All rise and set times are computed against YOUR actual horizon - not a flat mathematical one. Works completely offline after the initial download.

AR SKY VIEW & TIME-LAPSE
Point your camera at the sky to identify stars, planets, and constellations in real-time with augmented reality. Swipe the time slider to start a time-lapse animation and watch celestial motion unfold - planets crossing the sky, the Moon's monthly journey, satellite passes overhead.

LIVE SPACE WEATHER DASHBOARD
- Real-time aurora oval forecast with hemisphere selector
- Planetary Kp-index chart for geomagnetic storm tracking
- GOES X-ray flux chart showing solar flare activity over 3 days
- NOAA space weather alerts for storms and radio blackouts
- Hourly-updated NASA SDO solar images

TONIGHT'S BEST
Automatically generated list of the most interesting celestial objects and events visible from your exact location tonight - personalized recommendations based on your horizon and light pollution.

COMPREHENSIVE CATALOGS
- 45,000 stars with optional 2.5 million star catalog download
- 2,500+ NGC objects, complete Messier, Caldwell and Hidden Treasures catalogs
- 60,000+ minor planets with daily orbital updates
- 1,000+ comets with daily updates
- All Starlink satellites and ISS with pass predictions

SKY VIEW FEATURES
- Stunning photorealistic atmospheric scattering simulation
- Adaptive coordinate grid overlay
- Quick navigation to cardinal directions, zenith, and horizon
- Save your preferred default view position
- Night mode with red filter for preserving dark adaptation
- 3D Solar System view with VR/Cardboard support

PLANNING TOOLS
- Rise, set, and transit times calculated against your real horizon
- Automatically generated visibility reports
- User-defined event filter presets for quick access
- Favorite locations with drag-and-drop organization
- Manual coordinate entry in decimal or DMS format
- Twilight times and day length calculations

SOLAR AND LUNAR
- Current Sun imagery and sunspot data from NASA
- Moon phases with apparent planetary views
- Lunar librations and detailed orbital data
- Solar and lunar eclipse predictions worldwide

ADDITIONAL FEATURES
- Light pollution simulation showing sky brightness
- Meteor shower forecasts with peak activity times
- Conjunction dates for planets and Moon
- Home screen widgets for quick information
- Calculations accurate from 1900 to 2100

Continuously improved since 2011 - your complete astronomical toolkit.

Ratings and reviews

This app is one of the first ones I ever thought worthy of paying for, and it's been on every phone and tablet I've used for years. The recent rewrite the app went through has squashed some longstanding bugs and made things work with a little more polish, which is wonderful. Yes, there's a learning curve to it but it has way more information that most people will ever need.

I've used this app for so many years, but something happened in the recent updates. Moving around in the sky is no longer possible. Swiping across the screen moves the view a fraction of a degree, if at all. It has become entirely useless! Yes, I do have a budget phone, but any other app works flawlessly. No, disabling the horizon/landscape doesn't help. No, it's not the sensitivity setting. After deleting all data, it works. Once. After that, it no longer works at all. Help investigating this.

Very good, complete and capable astronomy app. My only two minor niggles are the on-screen controls are at times a bit small for a phone screen and there's no way to turn off diurnal motion, which means the chart drifts when zoomed in. But that's about it. However there's been no update (as far as I can tell) in 2+ years. Is the developer still active?

What’s new

Version 4.1.3

Bug fixes and stability improvements