FIND ELONGATION

Syntax

   FIND @name ELONGATION
 
        (2:2){ OF   @body
             | FROM @body  }
 
        (1:1){ GREATER THAN           @number
             | LESS THAN              @number
             | EQUAL TO               @number
             | BETWEEN  @number AND   @number
             | ABSOLUTE MINIMUM PLUS  @number(0:)
             | ABSOLUTE MAXIMUM MINUS @number(0:)
             | ABSOLUTE MINIMUM
             | ABSOLUTE MAXIMUM
             | LOCAL    MINIMUM
             | LOCAL    MAXIMUM  }
 
        (0:1){ WITHIN @name }
 
        STEP SIZE @number(0:)

Description

The FIND ELONGATION command locates intervals during which the elongation angle OF a target body as seen FROM an observing body satisfies a specified constraint.

The target body is represented as a sphere whose radius is equal to the longest equatorial radius of the tri-axial ellipsoid used to model it. The elongation of the body is defined to be the apparent angular separation between the centers of mass of the Sun and the target sphere.

Examples

Example 1

In the following example, the FIND ELONGATION command is used to determine intervals when Jupiter is more than 50 degrees from the Sun. The resulting schedule would typically be used to restrict searches for events involving the planet or its satellites.

   FIND CLEAR ELONGATION OF JUPITER
        FROM EARTH GREATER_THAN 50 DEGREES
        STEP SIZE 4 WEEKS;
 
   EXPORT  CLEAR TO JUP_CLEAR;

Example 2

In the following example, the FIND ELONGATION command is used to determine intervals when the elongation of Saturn is at a local maximum.

   FIND SAT_ELONG ELONGATION OF SATURN
        FROM EARTH LOCAL MAXIMUM
        STEP SIZE 4 WEEKS;

Notes

Finding the elongation of a body is not equivalent to finding its separation from the Sun, using the FIND SEPARATION command. The FIND SEPARATION command finds the separation between limbs of bodies.