Bright-star field: 5,044 stars to apparent magnitude 6 from d3-celestial stars.6.json.
Source: https://github.com/ofrohn/d3-celestial/blob/master/data/stars.6.json
Underlying data: XHIP, An Extended Hipparcos Compilation, Anderson E. and Francis C. (2012), VizieR V/137D.
https://cdsarc.cds.unistra.fr/viz-bin/cat/V/137D
Coordinates: J2000 equatorial, right ascension and declination in degrees.
Retrieved September 8, 2026.
Catalog sources and credits: https://github.com/ofrohn/d3-celestial#data

Copyright (c) 2015, Olaf Frohn
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
PHOTOGRAPHIC SKY AND REFERENCE LANDSCAPE (added September 8, 2026)

sources/milkyway.png is an unmodified copy of:
https://github.com/Stellarium/stellarium/blob/master/textures/milkyway.png
Full-sky Milky Way panorama: Axel Mellinger, University of Potsdam, Germany.
The Stellarium CREDITS.md section 4.4 records permission to modify and
redistribute the image with proper credit to the original image.
https://github.com/Stellarium/stellarium/blob/master/CREDITS.md
Our renderer changes display exposure, not the distributed source image.

sources/grossmugl.png is an unmodified copy of:
https://github.com/Stellarium/stellarium/blob/master/landscapes/grossmugl/grossmugl_leeberg_crop11.25_2048.png
Author: Guenther Wuchterl, Kuffner-Sternwarte.at.
Reference landscape: field near Leeberg, Grossmugl, Austria.
Distributed with Stellarium under GPL-2.0-or-later; full license is included in
sources/COPYING, and the original landscape configuration is sources/grossmugl.ini.
This is an illustrative reference landscape, not imagery of the user's location.
The original PNG files are provided alongside the map and in its source viewer.

The sky projection, WebGL renderer, and navigation implementation in this
project are original implementations. No Stellarium engine code is embedded.