# xSky vs Koehler Tutor

xSky and Koehler Tutor both sit at 4.3 stars, but that hides the real split: 79% of xSky's written reviews are positive against 43% of Koehler Tutor's. xSky also leads on ratings volume (80 vs 8). Koehler Tutor's advantage is update cadence (monthly vs every 3 months) and iOS requirement (12.0 vs 16.0). On price, rating, 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.

On the App Store both sit at effectively the same score — 4.3 for xSky against 4.4 for Koehler Tutor. That said, the two scores are not equally well evidenced: xSky has 80 ratings behind it against 8, so its average is the more settled of the two. Written reviews are what separate them: 79% of xSky's written reviews are positive against 43% of Koehler Tutor's.

xSky ships an update every 3 months, Koehler Tutor monthly. The most recent releases landed on October 20, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | xSky | Koehler Tutor |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.3 (80 ratings)](https://appshunter.io/ios/app/xsky/id850941042/reviews) | **[4.4 (8 ratings)](https://appshunter.io/ios/app/koehler-tutor/id1281328178/reviews)** |
| Number of ratings | **80** | 8 |
| Positive reviews | **79.4% of reviews** | 42.9% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free | Free |
| Size | 60 MB | 32 MB |
| Requires iOS | 16.0 | **12.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Oleg Sur](https://appshunter.io/developer/1454732575) | [Andrew Barlow](https://appshunter.io/developer/1229786938) |

## What reviewers say

### xSky

[App page](https://appshunter.io/ios/app/xsky/id850941042)

Explore the cosmos with a virtual telescope. Point your device at the sky to identify celestial bodies. Zoom in for detailed views and use a search function to locate specific objects.

**Highlights:** Virtual telescope functionality, Identify Sun, Moon, Planets, Stars, Galaxies, Zoom up to a million times, Screen lock to stop motion, Object search arrow, Soft music and sound effects

**Features:** macOS Compatibility

**In-app purchases:** none

**What reviewers like**

- 🔭 Realistic space simulation
- ✨ Beautiful visuals and music
- 👍 Easy to use interface
- 💡 Great for learning astronomy
- 💯 Highly accurate object identification

**What reviewers complain about**

- 🐛 App crashing issues
- 🧭 Location services not working
- 🔄 Inconsistent with reality (out of sync)
- 📱 Not optimized for all devices (e.g., iPhone 12)
- 🎛️ Hard to control

**Reported bugs**

- App keeps crashing
- Location services not working/picking a country
- App closes immediately upon opening
- App is glitchy and moves by itself
- Search button not working in horizontal position

**Requested features**

- Camera feature for high-quality photos
- Ability to turn down exposure for photos
- Facts read aloud about celestial objects
- Traditional constellation names (e.g., Virgo, Taurus)
- Show International Space Station or other satellites


### Koehler Tutor

[App page](https://appshunter.io/ios/app/koehler-tutor/id1281328178)

Learn the principles of Koehler illumination for microscopes. This app simulates microscope controls and image output, providing a virtual learning environment. It's a helpful tool for anyone needing to set up proper microscope illumination for optimal viewing.

**Highlights:** Virtual microscope simulation, Simulates control effects on image, Demonstrates correct control usage, Useful reminder for illumination setup, Applicable to all microscope brands

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

**In-app purchases:** none


## Frequently asked questions

### Is xSky free?

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

### Is Koehler Tutor free?

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

### Which has better reviews, xSky or Koehler Tutor?

Koehler Tutor is rated higher. xSky averages 4.3 out of 5 from 80 ratings, while Koehler Tutor averages 4.4 from 8 ratings.

### Do xSky or Koehler Tutor have ads?

Neither xSky nor Koehler Tutor shows ads.

### Which is updated more often, xSky or Koehler Tutor?

xSky ships an update every 3 months, and Koehler Tutor monthly. Most recently, xSky was updated on October 20, 2026 and Koehler Tutor on October 24, 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.*