Sky42 terms, plainly stated.
These terms apply when you download or use Sky42.
Sky42 is freeware published by DemaHub, for non-commercial use. This page summarizes what that means, permitted use, third-party data attribution, and liability limits. Sky42 has no paid tier — there is nothing here about purchases, licenses to buy, or refunds.
- Sky42 is freeware for non-commercial use — there is no purchase, no subscription, no license key.
- You may use Sky42 for personal, educational, academic and hobbyist purposes, on devices you own or control.
- Using Sky42 as part of a paid product or service, or otherwise for commercial purposes, requires a separate agreement — contact info@demahub.com.
- Sky42 itself and the catalogue data it draws carry separate, independent terms — see below.
- Sky42 is provided "as is," without warranty of uninterrupted or error-free operation.
- Support and legal contact requests can be sent to info@demahub.com.
Who is responsible
Sky42 is published by Davide De Martin through DemaHub.
Contact: info@demahub.com
Last updated: 2026-09-23
Terms of use
- Freeware, non-commercial use Sky42 is provided free of charge for non-commercial use: personal observing and study, teaching, academic research, and hobbyist projects. There is no purchase, no paid tier, and no per-seat license to buy from DemaHub for that use.
- What counts as commercial use Bundling Sky42 or its output into a paid product or service, using it to deliver a service you charge for, or otherwise deploying it for the benefit of a commercial operation, is commercial use and falls outside this free grant. Contact info@demahub.com to discuss a commercial license before that use.
- Permitted use Within the non-commercial scope above, you may use Sky42 on devices you own or control for lawful purposes. You are responsible for your own data, backups, and compliance with local laws.
- No self-update, nothing installed without asking Sky42 does not download or install anything on its own. The update check only ever tells you a newer version exists and opens this website; installing it is something you choose to do yourself.
- Warranty and liability Sky42 is provided on an "as is" and "as available" basis, without warranties of uninterrupted or error-free operation, positional accuracy beyond what its source data and numerical methods support, or fitness for a particular purpose. To the maximum extent permitted by law, DemaHub is not liable for indirect or consequential damages arising from use of Sky42.
- Changes to these terms These terms may be updated from time to time. Continued use of Sky42 after publication of updates constitutes acceptance of the updated terms.
Data sources keep their own licenses
Sky42's catalogues come from third parties, and each one carries its own license or attribution requirement, independent of the terms above. In particular, the deep-sky catalogue (OpenNGC, including its nebula outlines) is CC-BY-SA-4.0 — share-alike — so the pack built from it carries the same terms. Every catalogue Sky42 downloads arrives with an ATTRIBUTION.txt file beside it stating its source, credit and required citation, and the Data & licenses section of the Sky42 page lists them all.
This section describes the data license terms; the terms covering the Sky42 application itself are the ones above.
Support
For bug reports, feature requests, or questions about Sky42, contact info@demahub.com. The About dialog's "Copy details" button produces a block of build information worth pasting into a bug report.