KStars v3.8.3 is released on 2026.06.01 for Windows, Linux, and MacOS.
For Linux users, it's highly recommended to use the official KStars Flatpak hosted at Flathub.
This release brings major improvements to the Mount Modeler with artificial horizon filtering and uniform point distribution, significant connection speed optimizations, better guide streaming integration, and enhanced rotator handling. We've also fixed several scheduler and stability issues reported by the community. Here are the highlights:
Alignment & Mount Modeler
- Christian Kemper added Artificial Horizon filtering to the Mount Modeler wizard, allowing generated alignment points below the active horizon to be automatically filtered out. Candidate coordinate points (both generated AltAz coordinates and snapped catalog objects) are now checked and rejected if they fall into active artificial horizon regions.
- New Uniform Distribution mode generates points spread evenly across the visible sky using a Halton sequence, sampling in AltAz space to guarantee every point is above the configured minimum altitude. Points whose declination exceeds +/-80 degrees after conversion are rejected. The Any Stars, Named Stars, and Any Object modes now adopt this distribution internally and snap each generated position to the nearest qualifying object.
- Auto-sorted wizard output: points added by the wizard are automatically sorted in nearest-neighbour slew order, minimizing total slew distance. Users no longer need to click Sort after running the wizard. Clicking Sort during a run reorders only the remaining unvisited points, leaving completed rows undisturbed.
- The wizard now automatically configures the solver for each alignment point. Blind solves are used by default because no pointing model exists yet at the start of a run, so the mount's reported position may be significantly off. The GOTO mode is forced to Sync so the mount is updated after each successful solve. The original settings are saved and restored when the run finishes, is aborted, or is reset.
- Refactored point generation logic to eliminate duplicated generation and conversion math in the test suite, improving generator efficiency using a stateful sequence
- Toni Schriber fixed activation of the rotator button in the align module
- Fixed effective focal length calculation to use radians in the DSLR branch
Guide
- Thanks to Andreas Ruthner, guide streaming now correctly handles video stream window interaction. The video window no longer pops up when guide streaming starts, displays frames correctly when opened from the Capture module after a guide session, and now renders 16-bit mono stream frames (previously only 8-bit mono and RGB were handled).
- Andreas also fixed frame, binning, gain and exposure sync for streaming mode. When starting guide streaming, the module now applies the same frame settings that captureOneFrame() applies for single-frame captures. Previously, streaming mode skipped this setup entirely, causing stale values from other modules to remain active in the driver.
- Frame ROI and binning now sync on stream start, live gain updates apply immediately when the user changes the spinner during active streaming, and binning/exposure changes automatically stop and restart the stream
- Added 0.001-0.01s exposure values to the guide exposure spinner for fast streaming and daytime testing
Rotator
- Fixed several issues with Reversed rotator state not taken into account in various rotator operations
- Rotation now aborts if the Position Angle error keeps increasing due perhaps to reversed rotator behavior
Ekos Profiles & Connection
- Significantly cut down time to connect to INDI web manager by skipping DNS resolution if we already have an IP address specified for the remote host
- Fixed rare crash due to dangling clientManager pointer with test to verify the fix
Capture & Livestacking
- Use OpenCV debayering by default. Enforce even ROI selection to ensure bayer boundaries are respected.
- Always sync from INDI to overwrite shadow states in the Camera process
- Account for STREAM_FULL_DEPTH when streaming
- John Evans added support for Live Stacker Alt/AZ data via Seestar S30 Pro. It should support other telescopes in Alt/AZ mode.
- John added a gradient removal option to post processing in Live Stacker.
FITS Viewer & File Handling
- Use standard gzip compress instead of Qt own compression algorithm
- Support loading .fits.gz and .xisf.gz in the viewer
Scheduler & Observatory Automation
- Fixed scheduler freezes when loading ESL referencing many ESQ files (patch by Tomas). BUGS:519294
- Autopark should work over multiple nights now
- If observatory is not started, skip shutdown procedure
- Fixed issue where post-shutdown script run in infinite loop
- Fixed scheduler and capture scripts not running inside flatpak
Optical Trains & DBus API
- Added DBus call to set and get Pictures directory
- Fixed warning of missing devices when we already selected alternative devices in the optical train
Build & Infrastructure
- Use KSUtil to consolidate all calls to external executable so they can run correctly within a flatpak as well
- Within flatpak, run the external scripts on the host system since it may require libraries that are only available on the host system
- Christian Kemper fixed macOS iconutil failure by adding 256px and 512px icon sizes rendered from the existing SVG source, which are required by iconutil on macOS 15 (Sequoia)
- Wolfgang Reissenberger updated the Dockerfile to be based on installation scripts for all steps: INDI, StellarSolver, PHD2, GSC, openCV. All scripts are built uniformly such that existing packages or installations are preferred. If the package is missing, first installing the appropriate package is tried. If this fails, the package is built from sources
Stability & Bug Fixes
- Fixed crash reported in crash-reports.kde.org regarding invalid base device or message text. The check for message text now occurs earlier in the process to protect against this crash.
- Milhan Kim fixed test deadlock by replacing QTest::mouseClick with animateClick(), which posts the click through the event loop and prevents tests from hanging indefinitely on QDialog::exec() loops
- Fixed an issue where frequent temperature updates can cause the dark cover check to run indefinitely
- Hy Murveit fixed green lines display issue
- Fixed solution assignment
- Fixed crash and distorted artifacts in video streaming
- Replaced all abs and fabs with std::abs for consistency
- Modernized signals and slots
Many thanks to Christian Kemper, Andreas Ruthner, Toni Schriber, Hy Murveit, John Evans, Milhan Kim, Wolfgang Reissenberger, Tomas, and all others who contributed fixes and improvements to this release! Your work makes KStars better for everyone.
Download KStars v3.8.3 today and enjoy improved mount modeling, faster connections, and more reliable guiding!
