Using the Find Function

The ephemeris data of a column can be searched for specific values by means of the find function, which is used after the ephemeris calculation. To use the find function, select Edit -> Find from the main menu or press Ctrl-F. The Find value in column dialog appears. Select the column to be searched from the Column list (the current selected column is preset), the type of search from the Type list, and the start of search from the Start list.There are six options for Type and two options for Start of search.

The options for Type are:
Minimum	Finds the least value taking the sign into account.
Maximum	Finds the greatest value taking the sign into account.
Extreme	Finds the greatest absolute value (sign not taken into account).
Local minimum	Finds the next minimum value.
Local maximum	Finds the next maximum value .
Local extreme	Finds the next local extreme value, minimum or maximum.
The options for Start are:
in first row	Search begins in first row of selected column.
in current row	Search begins in current selected row of selected column. Row is selected by placing mouse cursor in it and clicking the left mouse button.

After choosing the Column, Type, and Start, click OK, the search is performed and the row of the ephemeris containing the required value is selected. If child windows (plots, chart) are shown, it's content will be updated (e.g if a XY-plot of the column has previously been created, a plot marker appears at the corresponding position, see the examples below) . To repeat the search beginning at the current selected row, press F3, which finds the next value meeting the selected search criteria.

In the following example, in which the calculation is at intervals of 12h, Mars's first station is found by searching its longitude column for a local extreme starting in the first row . The date and time 2007 Nov 15, 12:00h are returned with the longitude 102° 27' 3" and elongation 130° 14' 36".

In the next example, to find the second station, press F3, which performs the previous search again using the same search criteria, in the example for a local extreme, beginning in the current selected row. The date and time 2008 Jan 31, 00 :00h are returned with the longitude 84° 4' 40" and elongation 226° 21' 13".

Note that the find function internally operates to more number of places than displayed in the ephemeris table.

Limitations of the find function: Searches can fail if no value meeting the search criteria is found, in which case an error message 'The search was not successful' appears. For example, a local minimum must be followed by a greater value, a local maximum by a lesser value, a local extreme by a change of direction. A search for a local value that does not meet these criteria or does not exist after the current row produces an error. Finally, if the column value passes 360° = 0°, a search for a maximum returns the value closest to and less than 360°, a search for a minimum returns the value closest to and greater than 0°, a search for an extreme returns whichever comes first. These are obviously meaningless results. This limitation can be circumvented by reducing the range and interval for the calculation so that the results fall entirely below or entirely above 360° = 0°, which can be done by trial.