--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 = {
          "10-089_23.57.22_VMC_Img_No_1.png",
          "10-089_23.58.11_VMC_Img_No_2.png",
          "10-089_23.58.55_VMC_Img_No_3.png",
          "10-089_23.59.39_VMC_Img_No_4.png",
          "10-090_00.00.24_VMC_Img_No_5.png",
          "10-090_00.01.08_VMC_Img_No_6.png",
          "10-090_00.01.52_VMC_Img_No_7.png",
          "10-090_00.02.36_VMC_Img_No_8.png",
          "10-090_00.03.21_VMC_Img_No_9.png",
          "10-090_00.04.05_VMC_Img_No_10.png",
          "10-090_00.04.49_VMC_Img_No_11.png",
          "10-090_00.05.33_VMC_Img_No_12.png",
          "10-090_00.06.18_VMC_Img_No_13.png",
          "10-090_00.07.02_VMC_Img_No_14.png",
          "10-090_00.07.46_VMC_Img_No_15.png",
          "10-090_00.08.30_VMC_Img_No_16.png",
          "10-090_00.09.14_VMC_Img_No_17.png",
          "10-090_00.09.57_VMC_Img_No_18.png",
        }

dates = {
          celestia:utctotdb(2010, 03, 30, 23, 57, 22),
          celestia:utctotdb(2010, 03, 30, 23, 58, 11),
          celestia:utctotdb(2010, 03, 30, 23, 58, 55),
          celestia:utctotdb(2010, 03, 30, 23, 59, 39),
          celestia:utctotdb(2010, 03, 31, 00, 00, 24),
          celestia:utctotdb(2010, 03, 31, 00, 01, 08),
          celestia:utctotdb(2010, 03, 31, 00, 01, 52),
          celestia:utctotdb(2010, 03, 31, 00, 02, 36),
          celestia:utctotdb(2010, 03, 31, 00, 03, 21),
          celestia:utctotdb(2010, 03, 31, 00, 04, 05),
          celestia:utctotdb(2010, 03, 31, 00, 04, 49),
          celestia:utctotdb(2010, 03, 31, 00, 05, 33),
          celestia:utctotdb(2010, 03, 31, 00, 06, 18),
          celestia:utctotdb(2010, 03, 31, 00, 07, 02),
          celestia:utctotdb(2010, 03, 31, 00, 07, 46),
          celestia:utctotdb(2010, 03, 31, 00, 08, 30),
          celestia:utctotdb(2010, 03, 31, 00, 09, 14),
          celestia:utctotdb(2010, 03, 31, 00, 09, 57),
        }

 xarr = {
          -1907.905,
          -1931.196,
          -1952.042,
          -1972.819,
          -1993.999,
          -2014.638,
          -2035.207,
          -2055.704,
          -2076.593,
          -2096.943,
          -2117.220,
          -2137.421,
          -2158.002,
          -2178.048,
          -2198.015,
          -2217.903,
          -2237.710,
          -2256.989,
        }

 zarr = {
          7615.001,
          7560.499,
          7511.284,
          7461.811,
          7410.946,
          7360.952,
          7310.702,
          7260.197,
          7208.28,
          7157.26,
          7105.987,
          7054.461,
          7001.505,
          6949.472,
          6897.189,
          6844.657,
          6791.876,
          6740.056,
        }

 yarr = {
          -10904.135,
          -10916.549,
          -10927.300,
          -10937.675,
          -10947.894,
          -10957.503,
          -10966.729,
          -10975.573,
          -10984.219,
          -10992.281,
          -10999.955,
          -11007.238,
          -11014.281,
          -11020.768,
          -11026.859,
          -11032.551,
          -11037.843,
          -11042.626,
        }

obsno = 18
obstring = "30 March 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