About Valerian

Valerian is free, open-source, GPU-accelerated deep-sky image processing: it takes the subframes you capture of galaxies, nebulae and clusters and turns them into a finished image, on Linux, Windows and macOS, on x86_64 and ARM.

Dedication

Valerian is dedicated to my son Xaviar. His middle name is Valerian, because he was a very sleepy child, which suits software made for the long, quiet hours of the night sky.

The dedication is part of the licence terms: it must be kept in every copy and every modified version (see below). The desktop app's About page leads with it.

Its sister

Valerian is the deep-sky sibling of Helia, the solar stacker. The two share their core: file formats, GPU acceleration, the interface and the release pipeline, so an improvement to one lands in both. Helia's manual is at helia.12hobbies.studio.

Status

Valerian is pre-1.0. On the command line it calibrates, registers and stacks frames, removes the sky gradient, stretches, removes stars, plate solves, calibrates the colour against Gaia and drizzles, with GPU kernels for the heavy stages. The desktop app has the five steps (calibrate, register, stack, process, export) and this page; background extraction is not in the window yet. The scope and every decision taken so far are kept in the project's private issue tracker; this manual grows with the program, and each page says plainly what does not work yet. See the roadmap and a first session.

Copyright and licence

Valerian is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Additional terms apply under section 7 of the licence: the author attribution and the dedication above must be kept in every copy and every modified version, and modified versions must not be presented as the original. They are in ADDITIONAL-TERMS.md in the repository.

More from the author

Valerian is made by Laurence Horrocks-Barlow. If you are interested in anything else I make, visit 12hobbies.studio.