--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 = {
          "09-357_08.06.52_VMC_Img_No_1.png",
          "09-357_08.07.47_VMC_Img_No_2.png",
          "09-357_08.08.32_VMC_Img_No_3.png",
          "09-357_08.09.15_VMC_Img_No_4.png",
          "09-357_08.10.00_VMC_Img_No_5.png",
          "09-357_08.10.43_VMC_Img_No_6.png",
          "09-357_08.11.28_VMC_Img_No_7.png",
          "09-357_08.12.11_VMC_Img_No_8.png",
          "09-357_08.12.56_VMC_Img_No_9.png",
          "09-357_08.13.39_VMC_Img_No_10.png",
          "09-357_08.14.24_VMC_Img_No_11.png",
          "09-357_08.15.07_VMC_Img_No_12.png",
          "09-357_08.15.52_VMC_Img_No_13.png",
          "09-357_08.16.36_VMC_Img_No_14.png",
          "09-357_08.17.20_VMC_Img_No_15.png",
          "09-357_08.18.03_VMC_Img_No_16.png",
          "09-357_08.18.48_VMC_Img_No_17.png",
          "09-357_08.19.31_VMC_Img_No_18.png",
          "09-357_08.20.16_VMC_Img_No_19.png",
          "09-357_08.20.59_VMC_Img_No_20.png",
          "09-357_08.21.44_VMC_Img_No_21.png",
          "09-357_08.22.27_VMC_Img_No_22.png",
          "09-357_08.23.12_VMC_Img_No_23.png",
          "09-357_08.23.55_VMC_Img_No_24.png",
          "09-357_08.24.40_VMC_Img_No_25.png",
          "09-357_08.25.23_VMC_Img_No_26.png",
          "09-357_08.26.08_VMC_Img_No_27.png",
          "09-357_08.26.51_VMC_Img_No_28.png",
          "09-357_08.27.36_VMC_Img_No_29.png",
          "09-357_08.28.20_VMC_Img_No_30.png",
          "09-357_08.29.04_VMC_Img_No_31.png",
          "09-357_08.29.47_VMC_Img_No_32.png",
          "09-357_08.30.32_VMC_Img_No_33.png",
          "09-357_08.31.15_VMC_Img_No_34.png",
          "09-357_08.32.00_VMC_Img_No_35.png",
          "09-357_08.32.43_VMC_Img_No_36.png",
          "09-357_08.33.28_VMC_Img_No_37.png",
          "09-357_08.34.12_VMC_Img_No_38.png",
          "09-357_08.34.56_VMC_Img_No_39.png",
          "09-357_08.35.39_VMC_Img_No_40.png",
          "09-357_08.36.23_VMC_Img_No_41.png",
        }

dates = {
          celestia:utctotdb(2009, 12, 23, 08, 06, 52),
          celestia:utctotdb(2009, 12, 23, 08, 07, 47),
          celestia:utctotdb(2009, 12, 23, 08, 08, 32),
          celestia:utctotdb(2009, 12, 23, 08, 09, 15),
          celestia:utctotdb(2009, 12, 23, 08, 10, 00),
          celestia:utctotdb(2009, 12, 23, 08, 10, 43),
          celestia:utctotdb(2009, 12, 23, 08, 11, 28),
          celestia:utctotdb(2009, 12, 23, 08, 12, 11),
          celestia:utctotdb(2009, 12, 23, 08, 12, 56),
          celestia:utctotdb(2009, 12, 23, 08, 13, 39),
          celestia:utctotdb(2009, 12, 23, 08, 14, 24),
          celestia:utctotdb(2009, 12, 23, 08, 15, 07),
          celestia:utctotdb(2009, 12, 23, 08, 15, 52),
          celestia:utctotdb(2009, 12, 23, 08, 16, 36),
          celestia:utctotdb(2009, 12, 23, 08, 17, 20),
          celestia:utctotdb(2009, 12, 23, 08, 18, 03),
          celestia:utctotdb(2009, 12, 23, 08, 18, 48),
          celestia:utctotdb(2009, 12, 23, 08, 19, 31),
          celestia:utctotdb(2009, 12, 23, 08, 20, 16),
          celestia:utctotdb(2009, 12, 23, 08, 20, 59),
          celestia:utctotdb(2009, 12, 23, 08, 21, 44),
          celestia:utctotdb(2009, 12, 23, 08, 22, 27),
          celestia:utctotdb(2009, 12, 23, 08, 23, 12),
          celestia:utctotdb(2009, 12, 23, 08, 23, 55),
          celestia:utctotdb(2009, 12, 23, 08, 24, 40),
          celestia:utctotdb(2009, 12, 23, 08, 25, 23),
          celestia:utctotdb(2009, 12, 23, 08, 26, 08),
          celestia:utctotdb(2009, 12, 23, 08, 26, 51),
          celestia:utctotdb(2009, 12, 23, 08, 27, 36),
          celestia:utctotdb(2009, 12, 23, 08, 28, 20),
          celestia:utctotdb(2009, 12, 23, 08, 29, 04),
          celestia:utctotdb(2009, 12, 23, 08, 29, 47),
          celestia:utctotdb(2009, 12, 23, 08, 30, 32),
          celestia:utctotdb(2009, 12, 23, 08, 31, 15),
          celestia:utctotdb(2009, 12, 23, 08, 32, 00),
          celestia:utctotdb(2009, 12, 23, 08, 32, 43),
          celestia:utctotdb(2009, 12, 23, 08, 33, 28),
          celestia:utctotdb(2009, 12, 23, 08, 34, 12),
          celestia:utctotdb(2009, 12, 23, 08, 34, 56),
          celestia:utctotdb(2009, 12, 23, 08, 35, 39),
          celestia:utctotdb(2009, 12, 23, 08, 36, 23),
        }

 xarr = {
          1703.562,
          1662.916,
          1628.976,
          1596.003,
          1560.959,
          1526.985,
          1490.947,
          1456.074,
          1419.146,
          1383.468,
          1345.743,
          1309.344,
          1270.907,
          1233.001,
          1194.794,
          1157.182,
          1117.547,
          1079.429,
          1039.296,
          1000.730,
          960.159,
          921.201,
          880.245,
          840.944,
          799.654,
          760.056,
          718.477,
          678.624,
          636.800,
          595.797,
          554.698,
          514.447,
          472.243,
          431.845,
          389.501,
          348.985,
          306.533,
          264.981,
          223.393,
          182.722,
          141.081,
        }

 zarr = {
          5430.923,
          5474.784,
          5508.424,
          5538.736,
          5568.588,
          5595.374,
          5621.633,
          5645.076,
          5667.928,
          5688.2,
          5707.818,
          5725.08,
          5741.629,
          5756.352,
          5769.668,
          5781.356,
          5792.222,
          5801.33,
          5809.563,
          5816.219,
          5821.947,
          5826.268,
          5829.614,
          5831.713,
          5832.789,
          5832.772,
          5831.686,
          5829.652,
          5826.505,
          5822.445,
          5817.435,
          5811.642,
          5804.653,
          5797.109,
          5788.328,
          5779.111,
          5768.619,
          5757.543,
          5745.675,
          5733.331,
          5719.951,
        }

 yarr = {
          -2171.547,
          -2326.011,
          -2451.440,
          -2570.478,
          -2694.185,
          -2811.552,
          -2933.487,
          -3049.142,
          -3169.267,
          -3283.178,
          -3401.465,
          -3513.610,
          -3630.040,
          -3742.960,
          -3854.965,
          -3963.539,
          -4076.224,
          -4183.005,
          -4293.815,
          -4398.803,
          -4507.740,
          -4610.941,
          -4718.011,
          -4819.433,
          -4924.646,
          -5024.299,
          -5127.667,
          -5225.564,
          -5327.101,
          -5425.482,
          -5522.978,
          -5617.406,
          -5715.330,
          -5808.048,
          -5904.191,
          -5995.218,
          -6089.600,
          -6181.020,
          -6271.591,
          -6359.289,
          -6448.195,
        }

obsno = 41
obstring = "23 December 2009"

--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