illustris_tree.coffee

DecisionTree = require 'lib/decision_tree'

IllustrisTree = new DecisionTree 'illustris', ->
  @question 'Shape', 'Is the galaxy simply smooth and rounded, with no sign of a disk?', ->
    @help "The aim here is to divide featureless galaxies from all the rest. If you can see any interesting features at all, click "features or disk." Just occasionally you might see something that isn't a galaxy at all - the long streak of a satellite, for example, or an image swamped by light from a bright star. If this happens, just click "star or artifact". Click on the images to see larger examples."
    @answer 'Smooth', leadsTo: 'How rounded is it?', icon: 'smooth_round', examples: 5
    @answer 'Features or disk', leadsTo: 'Could this be a disk viewed edge-on?', icon: 'feature', examples: 5
    @answer 'Star or artifact', leadsTo: 'Would you like to discuss this object?', icon: 'star', examples: 3
  
  @question 'Disk', 'Could this be a disk viewed edge-on?', ->
    @help "Disc galaxies are very thin, so look different when viewed from the side. We're trying to find exactly edge-on galaxies with this question. If the galaxy looks needle-like, perhaps with a bulge at the centre, then click "yes," otherwise choose "no" (even for galaxies almost edge-on). Click on the images to see larger examples."
    @answer 'Yes', leadsTo: 'Does the galaxy have a bulge at its center? If so, what shape?', icon: 'yes', examples: 5
    @answer 'No', leadsTo: 'Is there any sign of a bar feature through the center of the galaxy?', icon: 'no', examples: 5
  
  @question 'Bar', 'Is there any sign of a bar feature through the center of the galaxy?', leadsTo: 'Is there any sign of a spiral arm pattern?', ->
    @help "Sometimes galaxies have a prominent straight "bar" running through their centre, and that's what we're looking for here. Click on the images to see larger examples."
    @answer 'Bar', icon: 'yes', examples: 5
    @answer 'No bar', icon: 'no', examples: 5
  
  @question 'Spiral', 'Is there any sign of a spiral arm pattern?', ->
    @help "Look carefully for spiral arms - remember they may be embedded in the disk and not that easy to see. Click on the images to see larger examples."
    @answer 'Spiral', leadsTo: 'How tightly wound do the spiral arms appear?', icon: 'yes', examples: 5
    @answer 'No spiral', leadsTo: 'How prominent is the central bulge, compared with the rest of the galaxy?', icon: 'no', examples: 5
  
  @question 'Bulge', 'How prominent is the central bulge, compared with the rest of the galaxy?', leadsTo: 'Is there anything odd?', ->
    @help "It's not always easy to tell, but look at the centre of the galaxy for a round bulge of stars which may obscure any bar and the spiral arms in this central region. Click on the images to see larger examples."
    @answer 'No bulge', icon: 'bulge_none', examples: 5
    @answer 'Just noticeable', icon: 'bulge_noticeable', examples: 5
    @answer 'Obvious', icon: 'bulge_obvious', examples: 5
    @answer 'Dominant', icon: 'bulge_dominant', examples: 5
  
  @question 'Odd', 'Do you see any of these odd features in the image?', ->
    @help "We're looking for signs that the galaxy is merging, is disturbed, or has other unusual/rare features. Ring galaxies have a bright circle of stars around the edge of the galaxy. Lenses and arcs are curved, detached bands of light that can be caused by gravitational lensing. Disturbed galaxies may have a kink or warp through the center. Irregular galaxies have shapes that are neither the smooth ellipticals or well-behaved spirals, like a big blob. Mergers can happen when galaxies pass near each other, often resulting in long tails of stars stripped out by gravity. Dust lanes are thin, dark features across a galaxy that resemble shadows. Click on the images to see larger examples."
    @checkbox 'Ring', icon: 'ring', examples: 5
    @checkbox 'Lens or arc', icon: 'lens', examples: 3
    @checkbox 'Disturbed', icon: 'disturbed', examples: 1
    @checkbox 'Irregular', icon: 'irregular', examples: 5
    @checkbox 'Other', icon: 'other', examples: 4
    @checkbox 'Merger', icon: 'merger', examples: 5
    @checkbox 'Dust lane', icon: 'dustlane'
    @answer 'Done', leadsTo: 'Would you like to discuss this object?', icon: 'yes'
  
  @question 'Round', 'How rounded is it?', leadsTo: 'Is there anything odd?', ->
    @help "Assess the relative roundness of the galaxy's shape, focusing on the edge of the stars that you can see in the galaxy. If the galaxy is very elliptical (cigar shaped; long in one direction and short in the other), look carefully for a central bulge or other indications that it might actually be an edge-on disk galaxy instead. Click on the images to see larger examples."
    @answer 'Completely round', icon: 'smooth_round', examples: 5
    @answer 'In between', icon: 'smooth_in-between', examples: 5
    @answer 'Cigar shaped', icon: 'smooth_cigar', examples: 5
  
  @question 'Bulge', 'Does the galaxy have a bulge at its center? If so, what shape?', leadsTo: 'Is there anything odd?', ->
    @help "Concentrate on the centre of the galaxy - if it has a smooth, uninterrupted, needle or lens-shape, then click "no bulge." Otherwise your options are "rounded" bulge or "boxy" (but boxy bulges are rare). Click on the images to see larger examples."
    @answer 'Rounded', icon: 'edge_round', examples: 5
    @answer 'Boxy', icon: 'edge_boxy', examples: 5
    @answer 'No bulge', icon: 'edge_none', examples: 5
  
  @question 'Spiral', 'How tightly wound do the spiral arms appear?', leadsTo: 'How many spiral arms are there?', ->
    @help "Astronomers classify spiral galaxies by how tight their arms are - you might find it easiest to assess this by looking at the arms close to the centre. Click on the images to see larger examples."
    @answer 'Tight', icon: 'spiral_tight', examples: 5
    @answer 'Medium', icon: 'spiral_medium', examples: 5
    @answer 'Loose', icon: 'spiral_loose', examples: 5
  
  @question 'Spiral', 'How many spiral arms are there?', leadsTo: 'How prominent is the central bulge, compared with the rest of the galaxy?', ->
    @help "Some spiral galaxies are rather complicated, but we want your best guess as to how many individual arms you can see. Note that the arms don't always begin at the very centre of the galaxy. If there are more than four arms, don't worry about counting them individually, but select the "more than 4" button. Click to see larger images."
    @answer '1', icon: 'spiral_1', examples: 5
    @answer '2', icon: 'spiral_2', examples: 5
    @answer '3', icon: 'spiral_3', examples: 5
    @answer '4', icon: 'spiral_4', examples: 5
    @answer 'More than 4', icon: 'spiral_4-plus', examples: 2
    @answer "Can't tell", icon: 'spiral_cant-tell', examples: 5
  
  @question 'Odd', 'Is there anything odd?', ->
    @help "We're looking for signs that the galaxy is merging, is disturbed, or has other unusual features. Click to see larger images."
    @answer 'Yes', leadsTo: 'Do you see any of these odd features in the image?', icon: 'yes', examples: 6
    @answer 'No', leadsTo: 'Would you like to discuss this object?', icon: 'no', examples: 4
  
  @question 'Discuss', 'Would you like to discuss this object?', ->
    @help "If you have any questions about this object, or think it may be interesting to others, or just have something to say, you can start a discussion on Talk by clicking "Yes". Talk will open in a new window - just close it to come back to the classification page."
    @answer 'Yes', icon: 'yes', talk: true
    @answer 'No', icon: 'no'

module.exports = IllustrisTree