Edge of Screen Radar

Alright, I got it working. I think it could probably be done better, but it works. So if anyone else ever needs it here it is:

 @script ExecuteInEditMode()
 //Radar Script adapted from PsychicParrots' radar script
 //Variables 
 var blipTexture     :Texture;
 var mapScaleX        :float         = 12;
 var mapScaleY        :float        = 8.5;
 var radarToggle        :boolean    = false;
 //Private Variables
 private var mapCenter = Vector2(Screen.width * 0.5,Screen.height * 0.5);
 //Draw GUI
 function OnGUI()
 {
     //Draw blips for asteroids
     if(radarToggle)
         DrawBlipsForAsteroids();
 }
  
 function DrawBlip(asteroid,aTexture)
 {
     var centerPos = transform.position;    //NOTE: If this is the position of the center of radar data collection 
                                         //if the game is not static, reference the player object
     var extPos = asteroid.transform.position;
  
     //First we need to get the distance of the asteroid from the center
     var dist = Vector3.Distance(centerPos,extPos);
     
     //Don't draw asteroids at ranges greater than this
     if(dist <= 30) 
     {
         var dx = centerPos.x - extPos.x; // how far to the side of the center is the asteroid?
           var dz = centerPos.z - extPos.z; // how far in front or behind the center is the asteroid?
         
         var xpos;
         var ypos;
         
         //These if statements essentially check which direction the astroid is from the center 
         //and set the position of the blip near the edge of the correct side of the screen
         if(dx > 0)
             xpos = 20;
         else
             xpos = Screen.width - 20;
             
         if(dz > 0)
             ypos = Screen.height - 20;
         else
             ypos = 20;
             
           //What's the angle to turn to face the asteroid - compensating for the center rotation?
           var deltay = Mathf.Atan2(dx,dz)*Mathf.Rad2Deg - 270 - transform.eulerAngles.y;
  
           //Just basic trigonometry to find the point x,y (asteroids location) given the angle deltay
           var bX = dist*Mathf.Cos(deltay * Mathf.Deg2Rad);
           var bY = dist*Mathf.Sin(deltay * Mathf.Deg2Rad);
  
           bX = bX * mapScaleX; // scales down the x-coordinate so that the plot stays within our radar
           bY = bY * mapScaleY; // scales down the y-coordinate so that the plot stays within our radar
              
         //Draw the blips within the constraints of the radar
         //Depending on which direction the asteroid is, let it move along the correct axis and lock the other axis in place
         if(dx > 12.5 || dx < -12.5)
         {    
               GUI.DrawTexture(Rect(xpos,mapCenter.y + bY,2,2),aTexture);
           }
           else if(dz > 9.3 || dz < -9.3)
           {
               GUI.DrawTexture(Rect(mapCenter.x + bX,ypos,2,2),aTexture);
           }
     }
 }
  
 function DrawBlipsForAsteroids()
 {
     //Find all game objects tagged asteroid
     var asteroids : GameObject[];
     asteroids = GameObject.FindGameObjectsWithTag("asteroid"); 
  
     //Iterate through them and call drawBlip function
     for (var asteroid : GameObject in asteroids)  
     { 
         //Don't draw a blip if the asteroid is in the game view
         if (!asteroid.renderer.isVisible)
             DrawBlip(asteroid,blipTexture);
     }
  
 }