Observer Pro vs Gravity by Vaonis
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Observer Pro
This app helps advanced astronomers and astrophotographers plan their observing sessions. It predicts object visibility, factoring in local obstructions, and provides weather forecasts. Manage observing lists and favorite sites to maximize your stargazing time.
- 14,000+ deep sky objects with photos
- Local horizon profile measurement
- Object visibility prediction charts
- Featured object recommendations
- Favorite observing site management
- Astronomical weather forecasts
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Observer Pro is an indispensable app for advanced astronomy observing and astrophotography planning. No more guessing when that galaxy emerges from behind that tree. No more estimating how many hours you'll be able to image an object. Observer Pro gives every astronomer the info they need to make the most of their observing right at their fingertips! What astronomers are saying: "Every astronomer with an iPhone should own this app!" - Astronomy Technology Today magazine "Observer Pro is the most impressive astronomy app that I have tried out. I enthusiastically commend it to you!" - Tom Mote, Professor Emeritus, Astronomy "I have been using it since the day it first became available and I cannot live without it now." - Sedat B., Cloudy Nights forum Feature highlights: • Over 14,000 deep sky objects included, all with closeup reference photos. No need to download anything after install! Sorting and search make it easy to sift through all of them to find which objects belong on your observing list. • Measure your local horizon profile in minutes with your iPhone. • Unique charts completely take the guesswork out of predicting object visibility. Your house, trees, mountains, or any other obstructions are completely factored in to all visibility charts. • New to astronomy? The Featured object list shows a list of objects specific to your location and local horizon that are great for observing right now. • Keep a list of your favorite observing sites, each with their own local horizon profile. Compare object visibility between sites to find the best spot to setup your scope. • There's a lot to observe! Observer Pro gives you a place to maintain a list of your favorite objects as well as an observing list that you can take with you to the eyepiece. • 7Timer! astronomical weather forecasts for your observing sites are viewable without leaving Observer Pro. They give you the outlook on cloud cover, seeing, transparency, and more. • Check out the in-app help to learn more about how to use the many features that come with Observer Pro. Keep up-to-date with the latest news at the Observer Pro blog: http://observer.pro/blog
Gravity by Vaonis
Transform your smartphone into a smart telescope to explore the cosmos. Capture stunning images of galaxies, nebulae, and star clusters with advanced image stacking. Observe the Sun and Moon with dedicated modes and educational content.
- Smartphone as smart telescope
- 25x optical zoom
- Live image stacking
- Sun and Moon observation
- Deep sky object photography
- Landscape and wildlife photography
- Educational cosmic content
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Gravity by Vaonis is the dedicated application for the Hestia instrument, transforming your smartphone into a smart telescope! Intuitive and user-friendly, this mobile application enables you to explore the Cosmos with ease. Track the activities of the Sun and the Moon, and immortalize your journey through the Universe by photographing galaxies, nebulae, and star clusters at your fingertips. CAMERA MODE Boost the power of your smartphone to achieve a 25x optical zoom on your mobile's camera, allowing you to observe the wonders of the Universe up close. IMAGE PROCESSING Make the invisible visible with Hestia's live image stacking technology. Choose your target and let the magic happen. Gravity by Vaonis enhances your observation experience using exclusive image processing algorithms. It intelligently combines and aligns multiple short-exposure images captured by your smartphone to create a single high-quality photograph. SPACE CENTER Monitor the real-time activity of the Moon and the Sun. LANDSCAPE MODE With Gravity by Vaonis, your surroundings become a new playground. Observe and photograph distant landscapes or even wild animals in their natural habitat. SOLAR AND LUNAR MODE Easily and safely observe the closest star to Earth during the day using Hestia's solar filter. Track the sun's activity and witness the evolution of solar spots and faculae. Track the sun's activity by examining the variations on its visible surface. Once night falls, admire the details of the lunar craters and track the different phases of the Moon. DEEP SKY MODE Observe the brightest objects in the deep sky. The Gravity by Vaonis application will guide you step by step to help you take your own photos of galaxies, nebulae, and star clusters. EDUCATIONAL CONTENT Gravity by Vaonis offers a comprehensive educational journey, providing you with the opportunity to explore the mysteries of the Universe.
Screenshots
Verdict
The clearest difference is price: Gravity by Vaonis at Free against Observer Pro's $13.99. Gravity by Vaonis also leads on update cadence (every 2 months vs every 6 months). Observer Pro's advantage is rating (4.6 vs 2.7) and review sentiment (79% vs 48%). On ratings volume, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Gravity by Vaonis is free to download; Observer Pro costs $13.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Observer Pro holds the better App Store score, 4.6 against 2.7. Both are backed by a comparable volume of ratings — 49 and 49 respectively. Written reviews point the same way: 79% of Observer Pro's written reviews are positive against 48% of Gravity by Vaonis's.
Observer Pro ships an update every 6 months, Gravity by Vaonis every 2 months. The most recent releases landed on September 21, 2026 and September 24, 2026 respectively.
| Parameter | Observer Pro | Gravity by Vaonis |
|---|---|---|
| Price | $13.99 | Free — better |
| Rating | 4.6 (49 ratings) — better | 2.7 (49 ratings) |
| Positive reviews | 79.2% of reviews — better | 47.7% of reviews |
| Number of ratings | 49 | 49 |
| Update frequency | Every 6 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone | iPhone |
| Requires iOS | 16.4 | 16.0 — better |
| Further details — not scored | ||
| Size | 241 MB | 331 MB |
| Age rating | 4+ | 4+ |
| Developer | Joshua Bury | Vaonis |
Customer experience
Observer Pro
Gravity by Vaonis
Bugs and requests
Observer Pro
Reported bugs
10 issues- App crashes when selecting catalog groupings (Galaxy, Planetary Nebulae, etc.)
- iOS keyboard doesn't dismiss on iPad after clicking Done
- Observer lists and custom data disappearing after app closure
- Search feature missing in version 1.4
- Continuous crashes since recent updates
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- Horizon drawing feature unreliable - drifts while drawing
- Menu items on far right side of screen unresponsive
- Incompatibility with iOS 8 (historical)
- App crashes on startup with certain iOS versions
- Weather feature broken
Requested features
16 requests- iPad native app with landscape mode support
- Search functionality restoration/improvement
- Export observer lists to other apps (Sky Safari, etc.)
- Support for planets, comets, and asteroids
- Observing notes and session logging
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- Field of view/scope focal length comparison
- Color object photographs
- Additional catalogs (Sharpless, etc.)
- Moon visibility in sky view
- Azimuth-based sorting for telescope positioning
- Filter options for object types
- Cross-device syncing between iPhone and iPad
- Print functionality for observing plans
- User-created custom catalogs
- Screen auto-rotation support
- Weather forecast integration
Gravity by Vaonis
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Observer Pro
No in-app purchases
Gravity by Vaonis
No in-app purchases







