AstroStacker vs AstroFITS
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
AstroStacker
Enhance your night sky photos by stacking multiple exposures into a single, detailed image. This app automatically aligns stars, reduces noise, and offers tools to refine your astrophotography results directly on your iPhone or iPad.
- Stack multiple night sky photos
- Automatic star alignment
- Noise reduction for clearer images
- Advanced editing tools
- Support for calibration frames (Pro)
- On-device processing
Read full descriptionHide full description
Stack your night-sky photos into one cleaner, more detailed image, right on your iPhone or iPad. Astrophotography stacking combines many exposures of the same sky. Astro Stacker finds the stars in every frame, lines them up and combines them, so random noise falls away and faint stars, the Milky Way and deep-sky targets come through. HOW IT WORKS 1. Take several separate photos of the same patch of sky from a tripod or stable surface. 2. Import them from Photos or Files into a Deep Sky Studio project. 3. Pick a stack mode and tap Stack. 4. Finish the result with Auto Stretch, styles and colour tools, then save or export. THREE SIMPLE STACK MODES - Quick: averages every frame for a fast first look. - Quality (default): rejects outliers such as plane and satellite trails, and leaves out the weakest frames. - Max Detail: the slowest and most selective mode, with finer alignment. AUTOMATIC STAR ALIGNMENT Stars are detected and matched in every frame, with sub-pixel alignment and a quality check for each frame. Stacking needs clear stars in your photos to line them up. CALIBRATION FRAMES (PRO) Add darks, flats, dark-flats and bias frames to correct hot pixels, thermal noise, vignetting and dust. Astro Stacker sorts frames by file name and exposure, so files named "dark" or "flat" are picked up for you. FINISH IN THE SAME APP - Auto Stretch to bring faint signal into view - Gradient removal for light pollution and uneven skies - Local contrast, vibrance, levels and per-channel colour balance - Styles: Natural, Nebula Pop, Cosmic Drama and Scientific, each with a strength slider - Before-and-after comparison - Quick Enhance for a single photo you've already taken FILES IN AND OUT - Import: photos from your library on Free; camera RAW, Apple ProRAW and FITS on Pro - Export: JPG, PNG, TIFF and FITS, with 16-bit export on Pro ON-DEVICE Stacking and editing run on your iPhone or iPad. You don't need a computer, and your source frames are not uploaded to stack them. An optional account backs up finished results. FREE AND PRO Free: 1 free stack with up to 10 light frames, and 3 saved results. Pro: unlimited frames and stacks, RAW, ProRAW and FITS import, calibration frames, 16-bit export and unlimited history. Choose monthly, annual or a one-time lifetime purchase. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the period, and you can manage them in your App Store account settings. GOOD TO KNOW - Moon, planet and solar stacking (Planet Lab) is coming soon. Today's stacking needs stars to align on. - Colour FITS files from one-shot-colour cameras are not debayered yet. - Star-trail stacking isn't supported, because every stack is aligned on the stars. Guides to capturing and stacking: https://astrostacker.co/guides Privacy Policy: https://astrostacker.co/privacy Terms of Use: https://astrostacker.co/terms Apple Standard EULA: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
AstroFITS
This app allows users to quickly open and view FITS files on iOS devices using GPU acceleration. It features automatic image stretching and supports various color formats and bit depths, making astronomical image analysis more accessible.
- 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
Read full descriptionHide full description
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
Screenshots
Verdict
The clearest difference is rating: AstroFITS at 2.0 against AstroStacker's 1.1. AstroStacker's advantage is update cadence (every 2 weeks vs monthly) and ratings volume (7 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. AstroStacker sells 3 in-app purchases, starting at $12.99 per month and AstroFITS sells 1 in-app purchase, starting at $0.99 per year. Whichever you choose, the download price is not the number that matters.
AstroFITS holds the better App Store score, 2.0 against 1.1. That said, the two scores are not equally well evidenced: AstroStacker has 7 ratings behind it against 1, so its average is the more settled of the two.
AstroStacker ships an update every 2 weeks, AstroFITS monthly. The most recent releases landed on November 12, 2026 and November 5, 2026 respectively.
| Parameter | AstroStacker | AstroFITS |
|---|---|---|
| Price | Free | Free |
| Rating | 1.1 (7 ratings) | 2.0 (1 ratings) — better |
| Positive reviews | 0.0% of reviews | — |
| Number of ratings | 7 — better | 1 |
| Update frequency | Every 2 weeks — better | Monthly |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Freemium | Free with in-app purchases |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 17 MB | 61 MB |
| Age rating | 4+ | 4+ |
| Developer | Ahmed Al-Mahmud | yong chong loh |
Customer experience
AstroStacker
AstroFITS
In-app purchases
AstroStacker
- AstroStacker app3 Days trial$12.991 Month
- AstroStacker app3 Days trial$99.991 Year
- AstroStacker app$219.00
AstroFITS
- Yearly Subscription$0.991 Year









