Changing brightness at night

I've noticed a strange situation when flying at night, in any aircraft. I'm using 3 LCD monitors and TripleHead2Go, so I always fly in the 3d cockpit. The problem (if it is a problem) is that when I pan around the cockpit, using the hatswitch on my CH yoke, the ambient level of brightness in the cockpit and the level of brightness in the view outside the cockpit (sky and ground textures) will change considerably, depending on the viewing angle. For example, at some angles, the cockpit (and outside scenery) becomes almost completely black. Then I pan down a little bit (or pan sideways) and everything gets a lot brighter, maybe a little too bright to be realistic. This only happens when flying at night.I'm using GEX and UTX for my ground textures. Anyone else seen this before or know what might be the cause?Thanks, Bob