Planet Stacker X

Planet Stacker X is a macOS application developed by Open Reel Software and distributed via the Rain City Astrophotography website. It is designed for planetary astrophotography, specifically using the method known as Lucky Imaging. This software allows Mac users to process high-speed planetary video footage into sharp, high-resolution images using frame selection, image stacking, and a range of enhancement tools. The software is not available for Windows or Linux, as it relies on macOS-specific frameworks and development kits.

Planet Stacker X, a free planet stacking and wavelet sharpening software for MacOS

Lucky Imaging is the foundation of how Planet Stacker X operates. This imaging technique avoids long exposures, which are susceptible to atmospheric turbulence, by capturing a rapid sequence of short exposures, usually video frames, from a telescope connected to a high-speed camera. Instead of averaging all frames equally, the software analyzes each frame's sharpness and selects only those with the least atmospheric distortion. These best frames are then aligned and stacked to increase detail and reduce noise. This technique has been used by amateur and professional astrophotographers for years to reveal subtle details on bright, compact objects like planets and the Moon.

Planet Stacker X streamlines this process into a workflow tailored for Mac users. First, users record a planetary video with a telescope and compatible camera. Supported video formats include SER and uncompressed AVI, which are common standards in planetary imaging. Once the video is loaded, users can choose automatic or manual modes for frame selection. In automatic mode, Planet Stacker X uses internal algorithms to assess frame quality. This assessment is based on wavelet frequency analysis of the entire frame, a method that prioritizes fine detail over multiple-point reference analysis. In manual mode, users get access to visual tools, including a sharpness graph and a live alignment preview, which allows for real-time feedback during the alignment phase. This is particularly useful when working with data that includes variable seeing conditions or planetary motion.

The stacking engine automatically normalizes exposure levels across the selected frames and adapts each one for alignment. This preparation helps to prevent misalignment artifacts during the final stack. Once the stacking is complete, the user enters the post-processing stage. Planet Stacker X includes a wide range of image processing tools specifically developed for planetary data. Wavelet sharpening is one of the central tools available, and the application supports both Gaussian and Starlet wavelet models. These filters enhance high-frequency details, such as the banding on Jupiter or surface texture on Mars, without introducing significant artifacts. For noise management, wavelet denoising can smooth the background or low-frequency noise while keeping edge sharpness intact.

Atmospheric and optical deconvolution tools are also included. These processes attempt to reverse the blurring caused by the Earth's atmosphere and the optical imperfections in the imaging system. The algorithms adjust the image based on models of atmospheric scattering and optical response functions, effectively reducing blur and increasing local contrast. Another important feature is RGB shift correction. Due to atmospheric dispersion or misalignment between color channels during capture, the red, green, and blue components of a planetary image can appear offset. Planet Stacker X provides fine control to manually or automatically shift and balance RGB data to produce accurate color alignment.

Full featured planetary astrophotography software for MacOS

Additional controls include tone curve adjustments, which let users shape image contrast on a curve-by-curve basis. Global noise reduction algorithms help clean up background noise while preserving important surface features. Standard exposure, gamma, and saturation sliders are also available to tune the overall brightness, dynamic range, and color vividness of the final image. These enhancements are designed to work in combination with stacking and sharpening tools, so users can iteratively improve their image with each adjustment pass.

Planet Stacker X supports batch processing for users who need to process multiple video files. After selecting and queuing multiple inputs, the application can run the stacking and enhancement workflow without further user input. This feature is helpful for those who want to leave the computer processing data overnight or work through large imaging sessions in a more automated way. Batch mode includes access to default presets, which can be customized to match a user’s preferred sharpening, alignment, or enhancement settings. The application remembers these preferences across sessions.

One limitation of the current version is the lack of support for multiple alignment points. Unlike some planetary stacking tools that allow users to select multiple areas of high detail across a planetary disc, Planet Stacker X uses a single whole-frame analysis. The developer notes that this approach typically yields better results for planets due to the nature of their features, though it may not perform as well on targets with more irregular or extended structures. Plans are in place to include alternative quality measures in future updates that would allow multiple-point alignment.

The application is focused exclusively on planetary astrophotography and does not currently support workflows for deep sky or landscape astrophotography. The algorithms and optimization techniques used in Planet Stacker X assume bright, high-contrast features that are common in planetary imaging but rare in wide-field or faint-object astrophotography. Despite this limitation, users are not prevented from experimenting with other data types, and the developer encourages experimentation as long as expectations are managed.

The story behind Planet Stacker X

The development of Planet Stacker X originated from the developer's own need for a native planetary stacking tool on macOS. Frustrated by the lack of suitable applications for M1-based Macs and the need to use emulators or virtual machines to run Windows-only software, the developer began working on a script to handle basic stacking functions. Over time, this script evolved into a full-featured application, incorporating user feedback and more advanced features. The software is actively maintained and receives regular updates as the developer continues to improve its capabilities based on new user needs and advances in planetary imaging techniques.

At this time, the developer is not accepting code contributions or direct financial donations. Instead, users who wish to support the broader astrophotography community are encouraged to donate to regional astronomical organizations such as the Seattle Astronomical Society or support retailers that specialize in amateur astronomy gear. Feedback and user reports are welcomed and appear to have played a significant role in shaping the software's direction.

Planet Stacker X is only available through the Mac App Store and is compatible with modern versions of macOS. Its interface is designed to integrate with macOS-native elements, leveraging hardware acceleration and system-level frameworks for performance and stability. As a result, the application benefits from smooth processing even on high-resolution video files, especially when run on Apple Silicon processors like the M1 or M2. Users with older Intel-based Macs may experience slower processing speeds, particularly during batch operations or when using high-resolution input files.

Documentation and help resources for the application are currently limited to the official website, which includes a frequently asked questions section, user guide summaries, and a contact form for support. While the interface is intuitive for users familiar with planetary imaging workflows, beginners may need to consult external tutorials or planetary imaging communities for best practices in video capture, camera settings, and telescope alignment. It is recommended that users become familiar with optimal capture parameters, including frame rate, gain, exposure, and filter usage, to produce data that benefits most from stacking and sharpening in Planet Stacker X.

Overall, the software is positioned as a standalone solution for Mac-based planetary astrophotographers who want to capture, stack, and enhance their data without switching to a different operating system or using emulation. Its reliance on native macOS features ensures a streamlined experience for users of Apple hardware, particularly those using newer systems with advanced processors and integrated GPUs. With continued updates planned and a focus on improving alignment tools and performance, Planet Stacker X appears to be evolving in response to the growing needs of the planetary imaging community on macOS.