Creating a New Ephemeris

The easiest way to create a new ephemeris is to use the Create new ephemeris dialog. This dialog will guide you through the appropriate steps in six pages.

Select Ephemeris->New from the main menu or press Ctrl+N . The Create new ephemeris dialog appears.

Step 1: Ephemeris data selection

This step determines what kinds of data are to be calculated. Select the ephemeris type and the quantities to be calculated. Only for the calculation of angular separations a reference object needs to be choosen. For more information see Ephemeris Type Selection.

In the above example geocentric ecliptical coordinates (longitude, latitude, and distance), the apparent visual magnitude and the angular separation from the sun (choosen as reference object) are selected.

Click Next to switch to the next page.

Step 2: Body selection

Select the bodies, for which the ephemeris calculation is to be performed, here. Depending on the ephemeris type choosen in the previous page, some bodies may be disabled. For other than the major bodies (asteroids, comets, fixed stars) click the More button. For more information see Body Selection.

In the above example only Mars is selected.

Click Next to switch to the next page or click Back to go back to step 1.

Step 3: Time span

Specify the time span of the ephemeris calculation here. There are three types of time span specification, wich are explained in detail in Time Specification. Select the time system (universal time UT or ephemeris time ET).A time shift may be applied to adjust the ephemeris calculation for the difference from the time at the Greenwich Meridian of either a standard time zone or the mean local time of the observer's location (see step 4).

For more information on time scale and time shift see Time span dialog.

In the above example 100 ephemeris calculations back and 100 ephemeris calculations ahead from the start time (24 December 2007, 12:00) with a time step of 12 hours will be calculated.