# SDO Viewer vs KeckWatch

The clearest difference is rating: KeckWatch at 4.3 against SDO Viewer's 3.0. KeckWatch also leads on review sentiment (83% vs 60%) and update cadence (every 5 weeks vs every 2 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

KeckWatch holds the better App Store score, 4.3 against 3.0. Both are backed by a comparable volume of ratings — 5 and 9 respectively. Written reviews point the same way: 60% of SDO Viewer's written reviews are positive against 83% of KeckWatch's.

SDO Viewer ships an update every 2 months, KeckWatch every 5 weeks. The most recent releases landed on October 7, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | SDO Viewer | KeckWatch |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (5 ratings)](https://appshunter.io/ios/app/sdo-viewer/id913723111/reviews) | **[4.3 (9 ratings)](https://appshunter.io/ios/app/keckwatch/id953228443/reviews)** |
| Number of ratings | 5 | **9** |
| Positive reviews | 60.0% of reviews | **83.3% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 5 weeks** |
| Monetization | Free | Free |
| Size | 6 MB | 147 MB |
| Requires iOS | 13.0 | **7.1** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Jérôme Diaz](https://appshunter.io/developer/334987620) | [Mike Smithwick](https://appshunter.io/developer/294198918) |

## 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


### KeckWatch

[App page](https://appshunter.io/ios/app/keckwatch/id953228443)

Explore the cosmos with detailed information on stars, planets, galaxies, and nebulae. Discover celestial objects using your device's compass and GPS, and stay updated with news from the W. M. Keck Observatory. Features a night-vision-friendly red interface and offline access.

**Highlights:** Offline celestial exploration, Real-time telescope status, Compass and GPS integration, Detailed object information, Hawaiian star names, Night vision red interface, Keck Observatory news

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is SDO Viewer free?

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

### Is KeckWatch free?

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

### Which has better reviews, SDO Viewer or KeckWatch?

KeckWatch is rated higher. SDO Viewer averages 3.0 out of 5 from 5 ratings, while KeckWatch averages 4.3 from 9 ratings.

### Do SDO Viewer or KeckWatch have ads?

Neither SDO Viewer nor KeckWatch shows ads.

### Which is updated more often, SDO Viewer or KeckWatch?

SDO Viewer ships an update every 2 months, and KeckWatch every 5 weeks. Most recently, SDO Viewer was updated on October 7, 2026 and KeckWatch on October 14, 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.*