--***************************************************************************
--                        markSpectralType function                         *
--                                                                          *
--  This function allows you to define a specific star spectral type and    *
--  then marks all stars of this type with a 10-pixel pink triangle marker. *
--                                                                          *
--  The original 17 lines of base code were written by Chris Laurel.        *
--  I have changed variable names, added comments, etc. to make the script  *
--  a little more understandable -- hopefully -- Don G.                     *
--***************************************************************************

  function markSpectralType(spectralType)
    local numOfStars = celestia:getstarcount()
    local counter = 0

    celestia:flash("Searching " .. numOfStars .. " stars...", 3)
    wait(3)

    while counter < numOfStars do
      star = celestia:getstar(counter)
      first, last = string.find(star:spectraltype(), spectralType, 1, true)

      if first == 1 then
         star:mark("#ff99ff", "triangle", 10)
      end

      counter = counter + 1
    end
  end


--***************************************************************************
--                                                                          *
--              Example of using the markSpectralType function              *
--                                                                          *
--***************************************************************************

  -- Define the spectral type to be marked...
  spectralType = "O"

  -- Clear all existing markers...
  celestia:unmarkall()

  -- Mark the requested Spectral Types...
  markSpectralType(spectralType)

  -- Make sure Marker display is ON...
  celestia:show("markers")

  -- The End
  celestia:flash("Done marking.", 3)