SKY MAP — CANOZCAN.DEV

Stars: XHIP, An Extended Hipparcos Compilation (Anderson & Francis, 2012),
VizieR V/137D, via Olaf Frohn's d3-celestial stars.6.json.
5,044 catalog stars with magnitude <= 6; J2000 equatorial coordinates.
https://github.com/ofrohn/d3-celestial
https://cdsarc.cds.unistra.fr/viz-bin/cat/V/137D

Constellation line figures and star names: d3-celestial,
constellations.lines.json and starnames.json. Original sources are listed at:
https://github.com/ofrohn/d3-celestial#files
Downloaded 2026-09-26. Converted into compact arrays in sky-catalog.js.
Data files are redistributed with the upstream BSD-3-Clause license:
https://canozcan.dev/assets/sky/d3-celestial-LICENSE.txt

Position calculations: Astronomy Engine 2.1.19, Donald Cross (MIT).
https://github.com/cosinekitty/astronomy
The full license is included in the served vendor/astronomy.js source.

The chart is an educational view of the hemisphere above an ideal sea-level
horizon, with north at the top and east on the left (looking up).
Stellar J2000 coordinates are rotated for the observation date, including
precession/nutation and normal atmospheric refraction. Stellar proper motion,
annual aberration, terrain, cloud cover, extinction and light pollution are
not modeled. Sun, Moon and planet positions are observer-dependent.
The source star catalog is limited to magnitude 6.

Location is approximate, obtained from Vercel's request geolocation headers.
Coordinates are rounded to 0.1 degree. VPNs and mobile networks can change the
apparent location. Manual city choices are explicitly labeled. This feature
does not store IP addresses or request device/GPS permission. Personalized
location responses are private and must not be cached.