US Naval Observatory Update US Naval Observatory Update
U.S. Naval Observatory Website Alternatives
In Investigation 1.3, Day and Night, students access the US Naval Observatory (USNO) site to obtain daylight or darkness data over the course of a year. USNO is updating their site and many parts are currently unavailable, including this page. Please refer to these alternate sites to help find the data for this part of the investigation.

NOAA Solar Calculator

Sunrise, sunset, daylight in a graph

The US Naval Observatory expects to have their site back up and operational no later than April 2020. It could be back up before that. If you would like to see if the site is working again now, you can access it here:

U.S. Naval Observatory