Emerald Observatory Credits

Copyright © 2010 Emerald Sequoia LLC, all rights reserved.

Astronomical algorithms and data tables derived from Lunar Tables and Programs from 4000 B.C. to A.D. 8000

, by Pierre Bretagnon & Jean-Louis Simon, copyright 1986, both published by Willmann-Bell, Inc. Used with permission of the copyright holder.

NTP code derived from public domain sources covered by these copyrights.

NASA images of the Earth have use terms described here