I was fortunate to see the green flash earlier in the year but have since read that it is possible to see colour separation before sunset if you project the image of the sun. I tried it here with the sun setting over Port Askaig on Islay. All I had on which to project the image was my hand. The image was inverted - you can see trees along the top of my hand. I was unable to spot colour separation along the top of the sun with this set up but will persevere.