Bright-star data: HYG Database v4.1, David Nash / Astronexus.
Source: https://github.com/astronexus/HYG-Database
Catalog: https://raw.githubusercontent.com/astronexus/HYG-Database/main/hyg/CURRENT/hygdata_v41.csv
License: Creative Commons Attribution-ShareAlike 4.0 International
https://creativecommons.org/licenses/by-sa/4.0/

Clearhour adaptation: retain stars with visual magnitude <=4, exclude Sol; retain HYG ID, name/designation, magnitude, J2000 Cartesian position and velocity. Extracted September 12, 2026. Derived data is distributed under the same CC BY-SA 4.0 license. No endorsement by the catalog author is implied.

The data license applies to bright-stars.js, independently of Clearhour application code.