FIRMAMENTO · BORTLE CERO — ATTRIBUTIONS

Concept, brand and photographs: Miguel / Bortle Cero. El puente estelar photographs with
Cyn Cabrera. Milky Way and eclipse time-lapses by Miguel (Milky Way: Playa La Perla,
Bahía Concepción, Mulegé, Baja California Sur, May 2025). Brand, photographs, videos and
personal narrative remain the property of their owners and are not covered by any code license.

EARTH
- Sky brightness layer (/textures/earth-lights-4k.webp): derived from the 2025 world atlas of
  artificial sky brightness by David Lorenz (binary tiles, astronomy/binary_tiles/2025), built on
  VIIRS nighttime lights by the Earth Observation Group, Payne Institute for Public Policy,
  Colorado School of Mines (VNL, CC BY 4.0). Same derivative published by Bortle Cero ·
  Observatorio (observatorio.bortlecero.com). Lorenz publishes the tiles openly without an
  explicit license; the VNL data are CC BY 4.0.
- Base map (/textures/earth-base.webp, /textures/earth-flat.webp): Natural Earth 1:50m via
  world-atlas (public domain).
- Day/night terminator computed live in the browser with astronomy-engine.

MOON
- Surface (/textures/moon-lro.jpg): NASA's Scientific Visualization Studio, CGI Moon Kit
  (Lunar Reconnaissance Orbiter). https://svs.gsfc.nasa.gov/4720/
- Tonight's phase and illuminated fraction computed with astronomy-engine.

STARS
- Star illustrations (/textures/stars/): generated with OpenAI imagegen for El puente estelar
  on 2026-09-20. Artistic depictions of spectral families, not photographs of real stars.
- Distance of Sirius (8.6011 ly): HYG 4.1, David Nash / Astronexus and HYG contributors,
  CC BY-SA 4.0, as published in El puente estelar's derived catalog.

SOFTWARE
- three.js — MIT License, © 2010-2026 three.js authors.
- astronomy-engine — MIT License, © Donald Cross.
- @vercel/analytics — MIT License.
- Space Grotesk — SIL Open Font License 1.1. Full text: /fonts/OFL.txt