Originally Posted by Squawk7700
Similar setup in the aircraft, and in IMC they actually move into a CLOSER formation than in VFR!
Squawk, you are completely wrong here. The same references for close formation are used whether Day, Night, VMC, or IMC. There is enough visibility in all but the nastiest of CB's to safely fly close formation in the standard positions. I've been in 4-ship formation IMC as the third man out, and not been able to see the lead aircraft, but fly on the wing of the second - it's all about good leadership and technique, and trusting the other guys around you.
At night, wingtip/nav/formation lights are used to assist the normal cues, as they provide some ambient lighting and situational awareness on what the lead aircraft is doing. Every now and then though you get one of those impossibly dark nights, where all you're formating on is lead's lights. Here you apply the principle of "If you can't see the stars, that's where the lead aircraft is"
Night formation - It's all good fun!