Welcome
Welcome to TPE (The Photographer’s Ephemeris®), a Sun, Moon and Night photography planning tool for outdoor photographers.
The idea for TPE was first hatched in March 2008 at a landscape photography workshop in Rocky Mountain National Park, Colorado. At the time, times and azimuths of sunrise, etc., were easily available online and in a handful of apps.
Glenn showed the class how to plot and interpret this information on a topographic map. It seemed like an opportunity to do that work digitally using online maps, and so TPE was born.
The technology of photography continues to develop apace, but the fundamentals of natural light endure. TPE for iOS has evolved considerably since its first incarnation in April 2010, and we expect it will continue to develop as mobile devices offer more capabilities. Send us your ideas for what you’d like to see in future versions!
We hope you enjoy using TPE to plan your outdoor and landscape photography; do show us what results you get from your planning!
Stephen + Alison
Crookneck Consulting LLC
Acknowledgements
- Selected maps by Thunderforest.com
- OpenStreetMap data courtesy of © OpenStreetMap contributors
- Time zone and elevation data courtesy of GeoNames.org
- Astronomical algorithms (mostly) from Astronomical Algorithms, 2nd Ed. by Jean Meeus
- Geodetic calculations based on T. Vincenty’s work, adapted from implementations by Mike Gavaghan and the US National Geodetic Survey
- Distance to horizon calculation based on the formula with refraction given by Andrew T. Young
- Adjustment for height above the horizon taken from the Explanatory supplement to the Astronomical Almanac by P. Kenneth Seidelmann
- Crescent moon visibility calculations based on “ A Method for Predicting the First Sighting of the New Crescent Moon ” by B.D. Yallop of HM Nautical Almanac Office
- Magnetic declination derived from the World Magnetic Model (WMM2015)
- Light pollution overlays from https://github.com/djlorenz/djlorenz.github.io
- Many thanks to Jeff Conrad for his expert comments and advice on TPE since 2009
- Sincere thanks to our users and, in particular, our beta testers, for the suggestions, comments, and insights that have helped shape the app.
Wake, the day draws near; I hear a song in the green coppice— a joyful nightingale, her voice pierces hill and vale: the night leans west to the Occident, the day rises from the Orient, the rosy-breasted dawn comes through the sombre clouds.
Copyright and Trademark
Except as noted below, this software is Copyright © 2010-2026 Crookneck Consulting LLC.
The Photographer’s Ephemeris is a registered trademark of Crookneck Consulting LLC.
Photographer’s Ephemeris, Photo Ephemeris, Photo Ephemeris 3D, The Photographer’s Transit, and Photo Transit are trademarks of Crookneck Consulting LLC
Notices
This app includes or accesses licensed software, services and data as set out below.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “ Software ”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “ AS IS ”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
ObjectiveWMM
Copyright © 2013-2023 Crookneck Consulting LLC
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “ Software ”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “ AS IS ”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
ObjectiveWMM includes portions of the WMM source code distributed by NGDC.
The WMM source code is in the public domain and not licensed or under copyright. The information and software may be used freely by the public. As required by 17 U.S.C. 403, third parties producing copyrighted works consisting predominantly of the material produced by U.S. government agencies must provide notice with such work(s) identifying the U.S. Government material incorporated and stating that such material is not subject to copyright protection.
