FIND APPARENT DIAMETER

Syntax

   FIND @name APPARENT DIAMETER
 
        (2:2){ OF   @body
             | FROM @body }
 
        (1:1){ GREATER  THAN          @number(0.001:)
             | LESS     THAN          @number(0.001:)
             | EQUAL    TO            @number(0.001:)
             | BETWEEM  @number AND   @number
             | ABSOLUTE MINIMUM PLUS  @number(0:)
             | ABSOLUTE MAXIMUM MINUS @number(0:)
             | LOCAL    MINIMUM
             | ABSOLUTE MINIMUM
             | ABSOLUTE MAXIMUM
             | LOCAL    MAXIMUM  }
 
        (0:1){ WITHIN   @name }
 
        STEP SIZE @number(0:)

Description

The FIND APPARENT DIAMETER command locates intervals during which the apparent angular diameter OF a target body as seen FROM an observing body satisfies a specified constraint.

The apparent angular diameter of the target is defined to be the angle, as seen from the observer, subtended by the sphere centered at the target body whose radius is the longest equatorial radius of the tri-axial ellipsoid used to model the body.

Examples

Example 1

   FIND MARS_MAX_DIAM APPARENT DIAMETER
        OF MARS FROM EARTH
        ABSOLUTE MAXIMUM
        STEP SIZE 10 DAYS;

Example 2

   FIND JUPITER_WIDE APPARENT DIAMETER
        OF JUPITER FROM EARTH
        GREATER THAN 50 ARCSECONDS
        STEP SIZE 10 DAYS;

Notes

Extrema in apparent diameter coincide with extrema in distance as computed by the FIND DISTANCE command.