Attribution

Star positions, constellation figures, asterisms and proper names are derived from d3-celestial by Olaf Frohn, at commit 7e720a3de062. Licensed under the BSD 3-Clause License.

Our build converts that data to compact binaries; positions are quantised to signed 16-bit unit vectors (about 6 arcseconds). This is a naked-eye application — do not rely on it for precision astrometry.

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.

ESA, The Hipparcos and Tycho Catalogues (ESA SP-1200, 1997). Astrometry from the Hipparcos mission underlies essentially every position in this app.

Yale Bright Star Catalogue, 5th Revised Edition (Hoffleit & Warren, 1991), for magnitudes, colour indices and traditional star names.

Planet positions, star charts and moon-phase renders are provided by AstronomyAPI. Requests are coarsened before they leave this server — coordinates to one decimal place, roughly 11 km — so your precise location is never sent to a third party or stored in our cache.

The following packages are used under the MIT License:

• nextapplication framework
• threeWebGL renderer for the sky
• astronomy-engineon-device ephemeris
• @clerk/nextjsauthentication
• @supabase/supabase-jsdatabase client
• stripepayments

Each package’s full licence text is distributed with it in node_modulesand is reproduced in the project’s THIRD_PARTY_LICENSES.md.