Main Input Window
This is the main window of the program, from here you
select whether you want Ephemeris data (GHA and Declination) or Rise and Set
data and also enter the time and date for any computation.
To find GHA and Declination
first select the body of
interest by pressing the arrow next to the Body input. That will bring up
the Body Selector screen.
All times are in
GMT, which is the same as UT listed in the Nautical Almanac. You can type in the hr min and
sec, or place the cursor on the one you wish to change and then use the up
and down arrows beside it to change values.
Likewise with the date, you can type in the values, or click the down
arrow for a convenient calendar display.
Then press Compute
to get these results:
Greenwich Hour Angle of Aries
Greenwich Hour Angle of the selected body
Declination of the selected body
Sidereal Hour Angle of the selected body
Semi-diameter of the body if sun or moon
Horizontal Parallax of the moon
Magnitude of a star or planet.
Press the Print button to view the Printing
Options, which can be
the screen output alone, or any sequence of data starting with this date and time. You select the time interval and the number of data points.
Rise and set data
select the sun icon for Sun data or the moon icon for Moon data after selecting time,
date and latitude (Lat).
is obtained from the sun rise and
set screen, which includes civil and nautical twilight times as well as
the GHA of Aries at the midpoint between them.
LAN data (local apparent noon)
The time of meridian
passage, peak height of the sun, and the Equation of Time are available in
the sunrise and set data.
The Lat input is only used for the rise and set data
for sun and moon, as well as Hc at LAN and the bearing of sun rise and
set. Type in the latitude of interest and then select N or S. You can use
whole degrees and minutes or decimal values; in any event the sum will be
computed and presented in the output screen.
Click the Help button on any screen to open this