# AstroFITS — Auto-Stretch and Transform

> iOS app for fast FITS file viewing and auto-stretching with GPU acceleration. (iPhone/iPad app by yong chong loh.)

- Source: https://appshunter.io/ios/app/astrofits/id6756322104 (this page in markdown: same URL + `.md`)
- Developer: [yong chong loh](https://appshunter.io/developer/393466709)
- Category: Photo & Video
- Price: Free with in-app purchases
- Rating: 2.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 17.0 · 61 MB
- Languages: American English
- Released: 2025-12-15
- Data updated: 2026-08-15
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/astrofits/id6756322104/reviews.md

## What is AstroFITS?

A simple app to open FITS file in iOS quickly using GPU. It has an auto-stretch feature. And works on FITS file with RGB or gray color. It handles BITPIX of 8,16,32,-32 and -64. It is designed and tested for Seetar FITS file. It takes about 2 seconds to open and automatically stretch a 50mb FITS file. Sample links are provided below. Enjoy! 

Use:
1. Download your FITS file to your phone File directory. 
2. Tap Image icon on the first top left.
3. Select your FITS file.
4. It will auto stretch. 
5. Adjust the image level. 
6. Adjust the image curve. 
7. Tap the second top icon to save image to Photo.

If you encounter an issue, please email to ustrainsit74@gmail.com with your FITS file as attachment. 

Sample:
Below are some FITS files for download.  
- https://drive.google.com/file/d/1Li8f1QH1u1R6U8RKZZ0kwW9LZ4cHCaXz/view?usp=share_link 
- https://drive.google.com/file/d/1MVuW1oa7qAjbfdl_iGUI-q7knE2ij67v/view?usp=share_link
- https://drive.google.com/file/d/1TE70gdDK3XmLx9-iB43I-uh6INq8FCaO/view?usp=share_link

Privacy policy and term of use (EULA) is at https://deepskycolor.blogspot.com/2018/12/privacy-policy-for-deep-sky-color-app.html

## Key features

- Open FITS files quickly on iOS
- GPU accelerated image processing
- Automatic image stretching
- Supports RGB and gray color
- Handles multiple BITPIX formats
- Save adjusted images to Photos

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Yearly Subscription | $0.99 | per year |



## Frequently asked questions about AstroFITS

### What is AstroFITS?

AstroFITS is an iOS application designed for quickly opening and viewing FITS files. It utilizes GPU acceleration for fast processing and includes an auto-stretch feature to enhance image visibility.

### How do I use AstroFITS?

To use AstroFITS, download your FITS file to your device, tap the image icon, select your file, and the app will automatically stretch it. You can then adjust image levels and curves before saving.

### What FITS file formats does AstroFITS support?

AstroFITS handles FITS files with RGB or gray color and supports BITPIX formats of 8, 16, 32, -32, and -64.

### How fast is AstroFITS?

The app is designed for speed, taking approximately 2 seconds to open and automatically stretch a 50MB FITS file.

### Does AstroFITS have ads?

No, AstroFITS does not contain advertisements, providing an uninterrupted user experience.

### What devices is AstroFITS compatible with?

AstroFITS is compatible with both iPhone and iPad devices.

### What is the age rating for AstroFITS?

AstroFITS has an age rating of 4+, making it suitable for a wide range of users.

### How often is AstroFITS updated?

The latest version, 1.4, was released on March 25, 2026, indicating ongoing development and support for the application.

## Version history (last 5 releases)

### 1.5 — 2026-08-03

- Fix the need to restart AstroFits for the thumbnail to display after subscribe. User may need to close and open the Files app to refresh the FITS file thumbnail.

### 1.4 — 2026-03-25

- Add auto debayer for type GRBG,GBRG,RGGB,BGGR. Seestar "save individual file" option saves each image as undebayer fits file. Seestar final image is a 3 channels debayered fits file. AstroFits app will auto debayer and display the image.

### 1.3 — 2026-03-11

- Fix no color for undebayer fits file.

### 1.2 — 2026-02-13

- Add thumbnail and Quick Look preview at the Files app.

### 1.1 — 2025-12-19

- Fix a bug.

## More apps by yong chong loh

- [Celestial Music Transcribe](https://appshunter.io/ios/app/celestial-music-transcribe/id1053723723)
- [SpiralCam - Astrophotography](https://appshunter.io/ios/app/spiralcam-astrophotography/id1446490348)
- [MilkyCam - Astrophotography](https://appshunter.io/ios/app/milkycam-astrophotography/id1456540708)
- [SaturnCam - Astrophotography](https://appshunter.io/ios/app/saturncam-astrophotography/id1459244951)
- [ImageCam - Astrophotography](https://appshunter.io/ios/app/imagecam-astrophotography/id1521156979)
- [VideoCam - Astrophotography](https://appshunter.io/ios/app/videocam-astrophotography/id1538035832)

All apps by yong chong loh: https://appshunter.io/developer/393466709

## Related topics

[seestar s50](https://appshunter.io/ios/topics/seestar-s50) · [seestar s30](https://appshunter.io/ios/topics/seestar-s30) · [zwo](https://appshunter.io/ios/topics/zwo)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-15.*