 
   showExistingAsteroids: ->
     return if @TRAINING_SUBJECT is null
-    for priorAsteroid in [ @TRAINING_SUBJECT.metadata.asteroids... ]
-      for surface in @markingSurfaceList
-        svgElement = surface.addShape 'circle', class: "ghost-mark", opacity: 1, cx: priorAsteroid.x, cy: priorAsteroid.y, r: 16, fill: "none", stroke: "rgb(200,20,20)", strokewidth: 1
+    xs = []
+    ys = []
+    x_sum = y_sum = null
+    for priorAsteroid, i in [@TRAINING_SUBJECT.metadata.asteroids...]
+      xs[i] = priorAsteroid.x
+      ys[i] = priorAsteroid.y
+      x_sum += xs[i]
+      y_sum += ys[i]
+    x_avg = Math.round(x_sum/@numFrames)
+    y_avg = Math.round(y_sum/@numFrames)
+    rad_x = Math.abs( (Math.max.apply null, [xs...]) - (Math.min.apply null, [xs...]) ) * 4
+    rad_y = Math.abs( (Math.max.apply null, [ys...]) - (Math.min.apply null, [ys...]) )* 4
+    
+    for surface in [@markingSurfaceList...]
+      svgElement = surface.addShape 'ellipse', class: "prior-asteroid", opacity: 0.75, cx: x_avg, cy: y_avg, rx: rad_x, ry: rad_y, fill: "none", stroke: "rgb(20,200,20)", 'stroke-width': 4
 
   sendClassification: ->
     @finishButton.prop 'disabled', true

    document.getElementById('frame-slider').value = 0 #reset slider to first frame
    @finishButton.prop 'disabled', true
    @onClickFlicker()
    @showExistingAsteroids()

  startLoading: ->
    @el.addClass 'loading'

User           = require 'zooniverse/models/user'
Subject        = require 'zooniverse/models/subject'
Sighting       = require '../models/sighting'
loadImage      = require '../lib/load-image'
Classification = require 'zooniverse/models/classification'
MarkingSurface = require 'marking-surface'
MarkingTool    = require './marking-tool'
InvertSvg      = require '../lib/invert-svg-image'

BIG_MODE = !!~location.search.indexOf 'big=1'
