--First stop time
celestia:settimescale(0)

--Then get variables containing Mars, the observer and the Celestia co-ord->km conversion factors
mars = celestia:find("Mars")
obs = celestia:getobserver()
km_per_mly=9466411.842
mly_per_km=1.0 / km_per_mly

--Clear render flags & labels
celestia:hide("orbits", "constellations", "boundaries", "markers", "grid")
celestia:hidelabel("planets", "moons", "spacecraft", "asteroids", "comets", "constellations", "stars", "galaxies", "locations")

--Preload Mars textures
mars:preloadtexture()

--Create arrays with the TASC generated MEX locations for each image
names = {
          "10-176_13.09.26_VMC_Img_No_1.png",
          "10-176_13.10.17_VMC_Img_No_2.png",
          "10-176_13.10.59_VMC_Img_No_3.png",
          "10-176_13.22.59_VMC_Img_No_19.png",
          "10-176_13.23.44_VMC_Img_No_20.png",
          "10-176_13.29.40_VMC_Img_No_28.png",
          "10-176_13.30.29_VMC_Img_No_29.png",
          "10-176_13.31.14_VMC_Img_No_30.png",
          "10-176_13.31.59_VMC_Img_No_31.png",
          "10-176_13.32.44_VMC_Img_No_32.png",
          "10-176_13.33.29_VMC_Img_No_33.png",
          "10-176_13.34.13_VMC_Img_No_34.png",
          "10-176_13.34.59_VMC_Img_No_35.png",
          "10-176_13.35.44_VMC_Img_No_36.png",
          "10-176_13.36.29_VMC_Img_No_37.png",
          "10-176_13.37.14_VMC_Img_No_38.png",
          "10-176_13.37.59_VMC_Img_No_39.png",
          "10-176_13.38.44_VMC_Img_No_40.png",
          "10-176_13.39.30_VMC_Img_No_41.png",
        }

dates = {
          celestia:utctotdb(2010, 06, 25, 13, 09, 26),
          celestia:utctotdb(2010, 06, 25, 13, 10, 17),
          celestia:utctotdb(2010, 06, 25, 13, 10, 59),
          celestia:utctotdb(2010, 06, 25, 13, 22, 59),
          celestia:utctotdb(2010, 06, 25, 13, 23, 44),
          celestia:utctotdb(2010, 06, 25, 13, 29, 40),
          celestia:utctotdb(2010, 06, 25, 13, 30, 29),
          celestia:utctotdb(2010, 06, 25, 13, 31, 14),
          celestia:utctotdb(2010, 06, 25, 13, 31, 59),
          celestia:utctotdb(2010, 06, 25, 13, 32, 44),
          celestia:utctotdb(2010, 06, 25, 13, 33, 29),
          celestia:utctotdb(2010, 06, 25, 13, 34, 13),
          celestia:utctotdb(2010, 06, 25, 13, 34, 59),
          celestia:utctotdb(2010, 06, 25, 13, 35, 44),
          celestia:utctotdb(2010, 06, 25, 13, 36, 29),
          celestia:utctotdb(2010, 06, 25, 13, 37, 14),
          celestia:utctotdb(2010, 06, 25, 13, 37, 59),
          celestia:utctotdb(2010, 06, 25, 13, 38, 44),
          celestia:utctotdb(2010, 06, 25, 13, 39, 30),
        }

 xarr = {
          2313.930,
          2287.343,
          2265.368,
          1878.045,
          1853.200,
          1654.188,
          1626.464,
          1600.935,
          1575.340,
          1549.681,
          1523.959,
          1498.748,
          1472.327,
          1446.418,
          1420.449,
          1394.419,
          1368.331,
          1342.183,
          1315.395,
        }

 zarr = {
          13184.71,
          13165.054,
          13148.413,
          12798.533,
          12772.55,
          12549.552,
          12516.409,
          12485.445,
          12453.975,
          12421.996,
          12389.508,
          12357.248,
          12322.998,
          12288.972,
          12254.43,
          12219.37,
          12183.791,
          12147.691,
          12110.249,
        }

 yarr = {
          -1408.452,
          -1461.858,
          -1505.790,
          -2250.272,
          -2296.158,
          -2655.868,
          -2704.883,
          -2749.782,
          -2794.570,
          -2839.245,
          -2883.802,
          -2927.255,
          -2972.559,
          -3016.752,
          -3060.818,
          -3104.755,
          -3148.561,
          -3192.231,
          -3236.730,
        }

obsno = 19
obstring = "25 June 2010"

--Set the initial time
celestia:settime(dates[1]);

--Go to Mars then write title
obs:track(mars)
celestia:flash("European Space Agency\nMars Express Visual Monitoring Camera\nObservation "..obstring, 15)
obs:goto(mars,5)
obs:goto((mars:getposition() + celestia:newvector(xarr[1], yarr[1], zarr[1]) * (mly_per_km)),5)
wait(10)
celestia:flash("Press 'M' for next image, 'N' for previous image.\nUse left and right arrow keys to rotate the\nplanet to the same orientation as the image.", 10)
wait(10)
celestia:showlabel("locations", "moons", "spacecraft")

--Create a function that goes to a given image number
gotoimage = function(imgno)
	
	celestia:settime(dates[imgno])
		
	obs:setposition(mars:getposition() + celestia:newvector(xarr[imgno], yarr[imgno], zarr[imgno]) * (mly_per_km))
		
	celestia:select(mars)
	
	obs:track(mars)
	
	celestia:flash(names[imgno], 60)	

end

--Create a function that will go to the next image in the series
next = function(goto)

	if (count + 1)>obsno then
		count = 1
	else
		count = count + 1
	end
	
	gotoimage(count)
end

--Create a function that will go to the previous image in the series
last = function()
	
	if (count - 1)<1 then
		count = obsno
	else
		count = count - 1
	end
  
    gotoimage(count)
end

--Create a counter holding the position of the current image
count = 1

--Set the position to the first image
gotoimage(count)

--Add the necessary keyboard callback code
keymap = { n = last, m = next }

celestia_keyboard_callback = function(key) 
     f = keymap[key]
     if f then 
        f() 
        return true
     end
        return false
end

celestia:requestkeyboard(true)
repeat
     wait(10)
until false