An official website of the United States government
Here’s how you know
Official websites use .gov A
.gov website belongs to an official government
organization in the United States.
Secure .gov websites use HTTPS A
lock (
) or https:// means you’ve safely connected to
the .gov website. Share sensitive information only on official,
secure websites.
[247] - Quarterly Journal of the Royal Astronomical Society, v. 23, p. 629, 1982.
Updated
Jun 29, 2011 11:28 AM
The boundaries shown on the maps above are approximate and are intended
only to portray the locations of named features and their rough extents.
Changes in the control network drop down are not reflected automatically on the map.
You may wish to select a different layer on the map to match the control network
for the geometry you are viewing.