Starry Sky Stacker is a Mac application that reduces noise in pictures of the night sky. The reduction in noise comes from combining a sequence of identical exposures into a single image. Starry Sky Stacker requires that an equatorial mount that ensures that stars move very little either during or between exposures is used during capture. (Note that alt-azimuth mounts are not suitable for use with Starry Sky Stacker because the stars appear to rotate within the frame both during and between exposures). Images must be RAW (from a supported camera), TIFF or JPEG. (FITS files are not supported. Astronomical cameras that use monochrome sensors with filters are not supported. See Restrictions and Requirements).
Starry Sky Stacker
aligns the images to compensate for errors in tracking,
assigns a quality estimate to each image,
allows the user to select images based on the quality estimate or manually and,
combines the images using four different algorithms (truncated mean with outlier rejection, mean with outlier rejection, max, min).
Starry Sky Stacker can
optionally subtract dark frames and
optionally apply flat-field corrections
Instructions for using Starry Sky Stacker are here.
Key advantages of Starry Sky Stacker are:
it is simpler and easier to use than most stacking programs
it is fast
it uses a proprietary alignment algorithm that produces excellent results
it computes 5 compositions of the selected images simultaneously allowing the user to easily choose which compositions to use.
Starry Sky Stacker can substantially reduce both shot noise and fixed-pattern noise in the final image, and correct for vignetting and other lens and sensor defects. Starry Sky Stacker is for pictures of the sky, with no foreground, taken with a tracking device so that the stars do not move within the frame. If you want to make pictures with stars as points above a landscape you should consider Starry Landscape Stacker.
Starry Sky Stacker requires Mac OS 10.14.6 or later. Starry Sky Stacker can process 100's of images with as little as 4GB of memory.
You can purchase Starry Sky Stacker in the Apple App Store. A free trial is available for download. Instructions for using Starry Sky Stacker are here. Starry Sky Stacker is also available in two bundles with other stacking apps.
Last updated March 2025 for version 1.5.0.