NAME:
  altoha
 PURPOSE: (one line)
  Convert an object altitude to its hour angle.
 DESCRIPTION:
 CATEGORY:
  Astronomy
 CALLING SEQUENCE:
  altoha,alt,dec,lat,ha,type
 INPUTS:
  alt  - Altitude of object above horizon in radians
  dec  - Declination of object in radians
  lat  - Latitude of observatory in radians
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
  ha   - hour angle for object (< 0 is East, > 0 is West)
  type - indicates the success of the conversion
           -1   object is always below ALT
            0   conversion ok, HA valid
            1   object is always above ALT
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  94/05/07 - Written by Marc W. Buie, Lowell Observatory
  2000/11/06, MWB, changed to permit vector inputs.