AstroStacker: Stack the Sky

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/