ABOVE TONIGHT — DATA SOURCES

Positions of the Sun, Moon and planets
Calculated in your browser with Astronomy Engine 2.1.19 by Don Cross, under the MIT licence. https://github.com/cosinekitty/astronomy

Stars
The 743 selectable stars are adapted from the HYG Database v4.1 by David Nash (Astronexus), which combines the Hipparcos, Yale Bright Star and Gliese catalogues. Licence: Creative Commons Attribution-ShareAlike 4.0 International, https://creativecommons.org/licenses/by-sa/4.0/. We kept 743 of its records and some of its columns, converted right ascension from hours to degrees, and added each star's constellation. Positions, distances and magnitudes are otherwise as published. The star data we publish is offered under the same licence. Source: https://github.com/astronexus/HYG-Database/tree/3bf37f4b2d5460e1278286320d1d62fab9b493c1 (the database is now also published at https://codeberg.org/astronexus/hyg).

Constellations
Constellation names, star names and designations, and constellation lines are adapted from D3-Celestial by Olaf Frohn, under the BSD 3-Clause licence. We keep the English and Latin names of the 88 modern constellations only and combine the fields with the star data. The lines show one Western convention and are not official International Astronomical Union boundaries. Source: https://github.com/ofrohn/d3-celestial/tree/7e720a3de062059d4c5400a379146a601d9010e0

Places
The built-in city list is our own compilation of geographic coordinates, rounded elevations and IANA time-zone identifiers; no third-party list is used. A location supplied by your device is rounded to 0.05 degrees before use.

Notes
Our notes on constellations, the Sun, Moon, planets and stars link to the open or primary sources they rely on. We link to those sources and do not copy their text.

Rendered altitude and azimuth are geometric and do not include atmospheric refraction. Rise and set calculations use Astronomy Engine's standard horizon correction.

Licences and attribution are listed in third-party-notices.txt.