b17 map problem at night/dawn

[alan CXA651]

Hi.
The otherday i did an early predawn flight in the b17 , and when i got the map out , due to cloud cover , to verify just where i was , i noticed on the single white direction bar , the arrowhead was missing , below is a short video , as i start predawn/dawn/daylight , while aircraft is parked , to show how the arrowhead is there in daylight , but missing in predawn/dawn lighting.

https://www.twitch.tv/cxa651/v/96248708

regards alan.

[alan CXA651]

Hi.
Update on problem of missing arrowhead on map at night, just fired up b17 predawn , dark cockpit, when i switched on cockpit lights arrowhead could just be seen but faint , yet under uv lights or no lights it disappears.
regards alan.