Your Android observatory with real-time sky view, AR, telescope control, and the only astronomy app that computes your local horizon from topographic data.
Recommended for new users. Start with the freemium app and unlock premium later with a subscription or one-time purchase.
Prefer paying once up front? Get Mobile Observatory Pro on Google Play. The same lifetime premium access is also available later inside Mobile Observatory.
Everything you need for astronomy, in your pocket
Point your phone and identify stars, planets, and constellations live
Explore planets, moons, and comets in an interactive orrery
ISS passes, Starlink trains, and 10,000+ satellites in real-time
2,500+ nebulae, galaxies, and star clusters with photos and details
50+ event types including eclipses, conjunctions, occultations, transits, and more
Aurora alerts, solar flares, ISS passes, and event reminders
Aurora forecast, Kp-index, solar flares, and NASA SDO images
Phases, eclipses, lunar features, sunspot data, and rise/set times
Real terrain profiles from NASA data for precise rise/set times
Auto-generated session plans based on your equipment and location
Connect your GoTo telescope and slew to any object with a single tap
Hipparcos, SAO, and extended catalogs with detailed star data
See Mobile Observatory in action
From first launch to expert observer
Point your phone at the sky and see stars, planets, and the Sun's path over your real 3D terrain.
Browse upcoming conjunctions, eclipses, ISS passes, and thousands of celestial objects with detailed data.
Generate optimized observing plans, control your telescope, and log your observations like a pro.
Scroll through real app screens — tap to enlarge






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Tools for astronomers, astrophotographers, and anyone who looks up
Explore the solar system in an interactive 3D view
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Point your camera and explore the sky
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Plan your observing sessions in advance
Detailed Sun and Moon information
Fresh 5-star feedback from astronomers around the world
"The update to version 4 brings several interesting graphical and functional improvements. It's incredibly realistic; the horizon profile at your observation location allows for more precise calculations of star rises and sets. The 3D view has been significantly improved, with updated graphics for the well-rendered planets, and every astronomical event is faithfully reproduced. A full 5 stars for this beautiful app, an indispensable tool for both amateur and professional astronomers."
"If you're wondering which special objects are in the constellation you're looking at right now, and when they can best be observed, then this app is exactly right for you. I've tried just about every astronomy app out there. My conclusion: by far the most valuable app for amateur astronomers who want to explore the night sky themselves with their own telescope."
"This app is simply fantastic and keeps getting better. It offers a huge variety of features, making it the most professional app in the Play Store."
"Version 4 is amazing: intelligently programmed, very well organized. Thank you for this excellent work!"
New users should begin with the freemium app, then unlock premium inside the app when they are ready. If you prefer buying up front, Mobile Observatory Pro remains available as the classic paid edition.
Recommended for all new users
Classic paid edition for users who prefer a separate upfront purchase
The story behind Mobile Observatory
Creator of Mobile Observatory
Wolfgang Zima spent years as a professional astronomer before finding his way into software development. After completing his PhD in Astronomy at the University of Vienna, he worked as a postdoctoral researcher at the Institute for Astronomy at KU Leuven in Belgium for five years. It was there that he discovered a passion for scientific software — writing tools for analyzing spectra of pulsating stars and building a CCD image simulator for ESA's PLATO mission, a space telescope searching for Earth-like exoplanets.
Mobile Observatory started almost by accident: when his Nokia phone broke on a mountain biking trip in late 2010, Wolfgang got his first Android phone and was surprised that no good astronomy apps existed. So he built one. First released in January 2011, Mobile Observatory has since grown into one of the most comprehensive astronomy apps for Android and has been continuously improved for well over a decade.
Wolfgang lives in Freiburg, Germany, where he works as a Senior Mobile Developer at sevdesk. He continues to develop Mobile Observatory with the same enthusiasm as on day one — now with the help of modern AI tools that let him bring new features to life faster than ever.
To draft text that effectively communicates facts to a reader, focus on clarity, verifiability, and logical structure. Key Strategies for Writing Fact-Based Text
In an age where information is everywhere but trustworthy facts can feel scarce, websites like FactsReader.com have emerged as popular destinations for curious minds. The platform claims to offer a wide range of articles—from history and science to pop culture and "amazing facts."
What is Facts Reader Com Free?
Have you used FactsReader.com? Share your experience in the comments below. And remember: the best fact-check is the one you do yourself.
Benefits of Using Facts Reader Com Free
You're looking for features of "Facts Reader Com Free". Here's what I found:
Not all free content is good content. Facts Reader employs a team of volunteer editors and fact-checkers who cite their sources at the bottom of every article. When you read a fact here, you aren't reading a random Reddit comment—you are reading a verified statement linked to primary sources.
To get the most out of this resource, you need to know the hidden tricks of the website. Here is a step-by-step guide:
If you’ve been searching for "facts reader com free" content, you’re likely looking for a way to learn something new every day. Here is everything you need to know about how this platform works and why it’s a top-tier resource for free knowledge. What is FactsReader.com?