HMS Sutherland illuminated the range with a para illum star shell, fired from her 4.5 inch main gun, say the Royal Navy.
The Royal Navy say in a release that the para(chute) illum(ination) flare bathes the area in an eerie greenish-white light for about 30 seconds.
“Such shells have been used by the British military since the Great War, but more recently the Navy has added the less obvious infra-red shell to its arsenal. It too is fired by a 4.5in main gun and bathes a specific area in light – infra-red light, invisible to the naked eye, but visible to friendly forces wearing the appropriate eyewear; night becomes day and, more importantly, the enemy has no idea he’s being lit up.
The illuminations came in the middle of 18 hours of gunnery during which time Sutherland laid down some serious lead: 180 rounds left the barrel of the 4.5in gun on the frigate’s forecastle (120 during the day shoot, 60 overnight) and crashed down on Cape Wrath as part of two exercises running concurrently.”