# SynLink vs Astro Stacker

The clearest difference is rating: SynLink at 4.3 against Astro Stacker's 1.0. SynLink also leads on in-app purchases (none vs 3) and device support (4 vs 2). On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. Astro Stacker sells 3 in-app purchases, starting at $12.99 per month. SynLink asks for nothing beyond the download.

SynLink holds the better App Store score, 4.3 against 1.0. Both are backed by a comparable volume of ratings — 3 and 5 respectively.

Both ship on a similar rhythm, roughly fortnightly. The most recent releases landed on October 25, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | SynLink | Astro Stacker |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.3 (3 ratings)](https://appshunter.io/ios/app/synlink/id6739761466/reviews)** | [1.0 (5 ratings)](https://appshunter.io/ios/app/astro-stacker-star-images/id6753679598/reviews) |
| Number of ratings | 3 | **5** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Fortnightly | Fortnightly |
| Monetization | Free | Free |
| Size | 221 MB | 17 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Suzhou UMa Technology Co., Ltd](https://appshunter.io/developer/1786910791) | [Ahmed Al-Mahmud](https://appshunter.io/developer/1844352476) |

## What reviewers say

### SynLink

[App page](https://appshunter.io/ios/app/synlink/id6739761466)

This professional controller facilitates astrophotography by offering broad compatibility with major camera brands and astronomical equipment. Its design emphasizes simplicity, restraint, and modernity for an intuitive user experience.

**Highlights:** Broad camera compatibility (Fujifilm, Canon, Nikon, Sony), Supports astronomical cameras, Controls equatorial mounts, Manages filter wheels and focusers, Modern and simple interface

**Features:** Vision Pro support

**In-app purchases:** none


### Astro Stacker

[App page](https://appshunter.io/ios/app/astro-stacker-star-images/id6753679598)

Transform your smartphone into a powerful astrophotography tool. This app uses advanced algorithms to combine multiple night sky photos, reducing noise and revealing hidden celestial details for professional-quality results.

**Highlights:** Advanced stacking algorithms (Average, Median, Maximum, Minimum), Intelligent and manual image alignment, Real-time processing and progress tracking, On-device processing, no cloud upload, Export high-resolution stacked images, Detailed processing insights and logs

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| AstroStacker app | $12.99 | per month |
| AstroStacker app | $99.99 | per year |
| AstroStacker app | $219.00 | one-time |


## Frequently asked questions

### Is SynLink free?

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

### Is Astro Stacker free?

Astro Stacker is free to download, with in-app purchases available.

### Which has better reviews, SynLink or Astro Stacker?

SynLink is rated higher. SynLink averages 4.3 out of 5 from 3 ratings, while Astro Stacker averages 1.0 from 5 ratings.

### Do SynLink or Astro Stacker have ads?

Neither SynLink nor Astro Stacker shows ads.

### Which is updated more often, SynLink or Astro Stacker?

SynLink ships an update fortnightly, and Astro Stacker fortnightly. Most recently, SynLink was updated on October 25, 2026 and Astro Stacker on October 28, 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.*