Azimuth  elevation input format:
Describe the horizon by entering lists of spaceseparated values corresponding to the
azimuth (0360 degrees) and angular elevation (090 degrees) of points on the horizon. If
you have a full 2pi field of view, i.e. no shielding, leave blank or enter zeros.
This procedure
means that in the field you should have approximated the horizon by a series of points with
straight lines between them. Note that this is not the same as approximating the horizon by
the average elevation angle in a series of equally spaced quadrants, octants, etc.: the latter procedure is
inappropriate because the relationship between rise angle and cosmicray shielding is
nonlinear, and it will underestimate the actual shielding in the case of large and variable horizon angles.
For example, if the horizon around you looked as follows:
You might approximate the horizon like this:
And enter the following series of points:
Azimuths:
0 55 115 235 310
Elevations:
3 0 5 0 0
This particular horizon has a shielding factor of 0.99995, that is, so small that we really didn't need to bother.
(Thanks to David Metsky at Dartmouth College for the 360degree panorama of the view from
Mt. Avalon that we've borrowed here)
