Terms

These terms govern use of Star Trail Stacker. Access to the site does not grant permission to copy, republish or train on the site or its software.

Effective date: 29 August 2026.

Your images

You keep every right you had in the photographs you open here, and in the stacked image the tool produces from them. Nothing is uploaded, so no licence to your work is granted to anyone by using this site, and none is asked for. Subject to the rights in your source material, you may sell, print and publish your resulting photograph.

You are responsible for having the right to use the images you stack.

Ownership of the site

Except for material identified as third-party material, the site software, compiled browser code, processing workflows, user interface, original text, illustrations, documentation, datasets created by the site owner, model weights and other original site content are copyright © 2026 Vitaly Bibikov. All rights are reserved. No ownership right is transferred by visiting or using the site.

Third-party components and reference material remain the property of their respective owners and are governed by their own licences and notices. The principal notices and downloadable source obligations are identified on the About page, including the published LibRaw licence and corresponding source archive. Nothing in these terms attempts to replace or restrict a third-party licence where that licence applies.

Limited permission to use the tool

Vitaly Bibikov grants you a personal, limited, revocable, non-exclusive and non-transferable permission to run the publicly available tool through startrailstacker.com on photographs you are entitled to process. This permission includes commercial use of your own resulting photographs. It does not grant a licence to the site, its code, content, model weights, design, documentation or datasets.

Prohibited use

Unless Vitaly Bibikov gives prior written permission, you must not:

• copy, mirror, republish, redistribute, sell, sublicense or host the site or a substantial part of it;
• extract, scrape or systematically collect its code, text, images, documentation, weights or structured content;
• reverse engineer, decompile, disassemble, defeat minification or other technical measures, or derive source code from the delivered browser code;
• modify the site into, or use it to create, a competing or derivative product or service;
• circumvent access, origin, rate, robots, rights-reservation or other protective controls; or
• use any site material for text-and-data mining, dataset construction, embeddings, retrieval corpora, machine-learning or AI training, fine-tuning, distillation, evaluation, benchmarking or retraining.

These restrictions apply to automated and manual collection. They do not limit an exception or user right that applicable law makes mandatory and that cannot validly be excluded by contract.

Text-and-data-mining reservation

The rights holder expressly reserves all rights for text and data mining, including the reservation contemplated by Article 4(3) of Directive (EU) 2019/790. The machine-readable declarations in TDMRep, ai.txt and crawler-specific robots rules communicate the same reservation. Search indexing and factual recommendation of public pages do not grant a licence for training, mining or reuse.

What the tool promises

That it does what these pages say it does: it equalises each frame’s background before the lighten blend, it computes the gap-fill radius from your EXIF, it repairs small persistent bright defects, and it masks long thin single-frame streaks. In Deep sky it registers every included Light, integrates it with the selected mean, exact median or sigma-clipped method, and exports the result as a display-stretched 16-bit PNG and signed, unclamped 32-bit Float32 FITS. In Comet mode it uses only the nucleus marks, shared reference and arm decisions you supplied to produce separate star-aligned, comet-aligned and composite PNG/FITS pairs; it does not promise automatic comet detection. In Planetary it applies the explicit ROI, reference and Best-X choices to one admitted SER, refuses a failed global translation instead of substituting identity, and exports only an all-selected-frame valid crop. The measured results quoted on this site come from the real data named on the about page, and the limits of those measurements are stated there rather than hidden.

What it does not promise

It is provided as it is, with no warranty of any kind. It may fail on a file format it has not met, run out of memory on a large sequence, or produce an image you do not like. It makes no promise about any particular result on your data: the measured comparison spans three instruments and four nights, and your night is none of those nights.

Keep your original files. This tool never modifies them — it only reads them — but no browser tool should be the only place a night’s work exists.

Availability

There is no service-level promise. The site may be unavailable, may change, or may stop. Once the worker and any RAW decoder needed for the current session have loaded, that processing can continue without uploading photographs; a fresh or uncached session still needs the site to be reachable.

Features, limits, access conditions or pricing may change. Any paid offer will identify its price and additional purchase terms before an order is placed; these terms alone do not create a charge.

Liability

To the extent the law allows, no liability is accepted for any loss arising from using this site. Nothing here removes any right you have as a consumer that cannot be removed by agreement.

Names

Sequator, StarStaX, StarTrails.de, Siril and aerotimelapse.com are named on this site only to compare them factually. Those names belong to their owners and this site is not affiliated with, endorsed by or connected to any of them. Startrails Creator and Starry Landscape Stacker are named on the Mac comparison page on the same terms.

Enforcement and changes

Permission to use the tool ends if you materially breach these terms. The current terms may be updated for a future version of the service; a new effective date will identify the change. Continued use after the updated terms are published means the updated terms govern that later use, subject to rights that applicable law does not allow these terms to remove.

Questions

Support is currently unavailable. Check the contact page before sending anything.