# AstroFileViewer vs SharpStacker

The clearest difference is iOS requirement: AstroFileViewer at 16.4 against SharpStacker's 18.6. On price, update cadence, 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.

AstroFileViewer ships an update every 11 days, SharpStacker fortnightly. The most recent releases landed on September 19, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | AstroFileViewer | SharpStacker |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/astrofileviewer/id6760240080/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 11 days** | Fortnightly |
| Monetization | Free | — |
| Size | 1 MB | 17 MB |
| Requires iOS | **16.4** | 18.6 |
| Devices | iPhone, iPad | **iPhone, iPad, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Joerg Klaas](https://appshunter.io/developer/1879846001) | [LUIGI VANNOZZI](https://appshunter.io/developer/6783673110) |

## What reviewers say

### AstroFileViewer

[App page](https://appshunter.io/ios/app/astrofileviewer/id6760240080)

View astronomical image files like FITS and XISF on your iPhone or iPad. Get an early impression of your data with PixInsight-compatible auto-stretching, gradient control, and noise reduction. Fun and useful for astrophotographers.

**Highlights:** Open FITS and XISF files from various sources, PixInsight-compatible STF auto-stretch, Mono and RGB image support with OSC debayer, Dark point and contrast sliders, Color saturation adjustment, GPU bilateral denoise, Gradient correction

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

**In-app purchases:** none


### SharpStacker

[App page](https://appshunter.io/ios/app/sharpstacker/id6783673108)

**In-app purchases:** none


## Frequently asked questions

### Is AstroFileViewer free?

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

### Is SharpStacker free?

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

### Do AstroFileViewer or SharpStacker have ads?

Neither AstroFileViewer nor SharpStacker shows ads.

### Which is updated more often, AstroFileViewer or SharpStacker?

AstroFileViewer ships an update every 11 days, and SharpStacker fortnightly. Most recently, AstroFileViewer was updated on September 19, 2026 and SharpStacker on September 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.*