Colour images

First try

device,true_color=24,decomposed=0,retain=2    ;or use set_col
window,0,retain=2
loadct,39
tvlct,r,g,b,/get
tv,bytscl(meteosat)
write_png,'~lecjm/out_39.png',tvrd(true=1),r,g,b

and

device,true_color=24,decomposed=0,retain=2 ; or use set_col
window,0,retain=2
load_sst_ct,r,g,b ; or load_sst_ct,r,g,b,course=1 in LINUX teaching lab
tv,bytscl(meteosat) ; or 
write_png,'~lecjm/out_sst.png',tvrd(true=1),r,g,b

(you will need to restart IDL, and reload the data, to get the device,true_color=24,decomposed=0,retain=2 line to work).

The different colour tables make a significant difference (remember this when you do/look at plots for actual science!)