# Star catalogue

`stars.json` is a subset of David Nash's HYG v4.0 catalogue, selecting stars of apparent magnitude ≤ 5.5 and retaining id, Hipparcos id, proper name, right ascension (hours), declination (degrees), and apparent magnitude. The Sun is excluded.

Source: https://github.com/astronexus/HYG-Database/blob/main/hyg/CURRENT/hygdata_v40.csv.gz
Copyright David Nash and catalogue contributors. Data licensed under Creative Commons Attribution-ShareAlike 4.0: https://creativecommons.org/licenses/by-sa/4.0/. This transformed subset is distributed under the same license. No endorsement implied.

Chart calculations use the US Naval Observatory's approximate sidereal time and horizon-coordinate formulas: https://aa.usno.navy.mil/faq/GAST and https://aa.usno.navy.mil/faq/alt_az. Epoch J2000 positions; no precession, refraction, atmospheric extinction, or proper-motion correction. Intended as an evocative sky chart, not a navigation tool. Constellation segments are selected familiar asterisms, not an exhaustive set of IAU boundaries. Stars are drawn even in daylight. The brand constellation overlay is symbolic.