Astronomical Event Calculator

The Date / time calculator allows the computation of

the instants of equinoxes and solstices

the instants of start of the Besselian years

the instants of lunar phases (new moon, first quarter, full moon, last quarter)

the instants of planetary configurations (oppositions, conjunctions and greatest elongations)

the instants of passages of perihelion (perigee), aphelion (apogee) and nodes

Select Tools->Astronomical Event Calculator from the main menu. The Astronomical event calculator window appears. A start time must be specified for all calculations. The initial start time is taken from the current selected cell of the ephemeris table and can be changed in the Start time box. The number of events to be calculated before and after the start time may be specified in Steps ahead and Steps back. All calculations are performed with respect to the selected time shift and time scale (see Time span). Again, the initial values of time shift and time system are taken from the ephemeris table and can be changed by the appropriate boxes. Finally select the type of events to be calculated. Navigate through the tree structure by clicking it’s nodes or entries. When an entry in the tree structure is selected a calculation will be performed. The results are shown in the list on the right part of the window. A contextual menu, which allows quick navigation in the list and clipboard operations, is assigned to the list. Right click somewhere on the list and the menu appears. In the example each 12 instants of oppositions of Mars before and after 1 January 2007 are calculated. The Astronomical Event Calculator is accessible from the Time span dialog too.