# SDO Viewer vs Hubble Space Telescope Tracker

The clearest difference is review sentiment: SDO Viewer at 60% against Hubble Space Telescope Tracker's 0%. SDO Viewer also leads on rating (3.0 vs 1.0) and in-app purchases (none vs 1). On price, ratings volume, update cadence and device support there is nothing between them.

Both are free to download. Hubble Space Telescope Tracker sells 1 one-off in-app purchase. SDO Viewer asks for nothing beyond the download.

SDO Viewer holds the better App Store score, 3.0 against 1.0. Both are backed by a comparable volume of ratings — 5 and 2 respectively. Written reviews point the same way: 60% of SDO Viewer's written reviews are positive against 0% of Hubble Space Telescope Tracker's.

SDO Viewer ships an update every 2 months, Hubble Space Telescope Tracker every 3 months. The most recent releases landed on June 1, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | SDO Viewer | Hubble Space Telescope Tracker |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.0 (5 ratings)](https://appshunter.io/ios/app/sdo-viewer/id913723111/reviews)** | [1.0 (2 ratings)](https://appshunter.io/ios/app/hubble-space-telescope-tracker/id6468819172/reviews) |
| Number of ratings | **5** | 2 |
| Positive reviews | **60.0% of reviews** | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 2 months** | Every 3 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 6 MB | 72 MB |
| Requires iOS | 13.0 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Jerome Diaz](https://appshunter.io/developer/334987620) | [KAKHA GIORGASHVILI](https://appshunter.io/developer/1501353984) |

## What reviewers say

### SDO Viewer

[App page](https://appshunter.io/ios/app/sdo-viewer/id913723111)

Access and view the latest images from the Solar Dynamics Observatory. Receive push notifications when new images become available, keeping you updated on solar activity.

**Highlights:** Download SDO images, Display latest solar images, Push notifications for new images, Courtesy of NASA/SDO science teams

**Features:** macOS Compatibility

**In-app purchases:** none


### Hubble Space Telescope Tracker

[App page](https://appshunter.io/ios/app/hubble-space-telescope-tracker/id6468819172)

Follow NASA's Hubble Space Telescope mission in real time. Explore a gallery of stunning images, engage in discussions, and learn about space. Receive notifications for new discoveries and test your knowledge with quizzes.

**Highlights:** Real-time mission progress, Image gallery, Discussion forums, Notifications for new images, 3D Solar system model, Ask an Astronomer feature

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $2.99 | one-time |


## Frequently asked questions

### Is SDO Viewer free?

SDO Viewer is free to download, with no in-app purchases.

### Is Hubble Space Telescope Tracker free?

Hubble Space Telescope Tracker is free to download, with in-app purchases available.

### Which has better reviews, SDO Viewer or Hubble Space Telescope Tracker?

SDO Viewer is rated higher. SDO Viewer averages 3.0 out of 5 from 5 ratings, while Hubble Space Telescope Tracker averages 1.0 from 2 ratings.

### Do SDO Viewer or Hubble Space Telescope Tracker have ads?

Hubble Space Telescope Tracker shows ads; SDO Viewer does not.

### Which is updated more often, SDO Viewer or Hubble Space Telescope Tracker?

SDO Viewer ships an update every 2 months, and Hubble Space Telescope Tracker every 3 months. Most recently, SDO Viewer was updated on June 1, 2026 and Hubble Space Telescope Tracker on September 9, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*