It was interesting how they conducted the seminar. They began by taping over the gaps on the doors, at the door thresholds, air ducts, shielding the white light emanating from the projector, etc. The purpose was to make the room as dark as possible. The Power Point display featured red lettering on a black background thorughout the presentation. Even from the front row of seats it was hard to read.
An image was then shown but no one could make it out. We were promised it would be shown again at the end of the seminar. As time went by the lettering on the screen began to be ever more readable.
By twenty minutes in the dark, some people could read the red type. Thirty minutes about half the attendees. Forty-five minutes almost all. (I have to wonder about those who never became fully night adapted.) At the end of the seminar before the lights came up, the image was again shown. It was a darkened Blackhawk helicopter as seen on a moonless night, 200 yards distant. It was a real photo.
Of course, the blackhole illusions were discussed. A pilot's best defense is adequate adaptation to night. 30-45 minutes is sufficient. The human eye does not continue to night adapt beyond 45 minutes. An occasional white light when night adapted will not result in losing your night vision.
I gained some insight into what autokinesis really is. It is more than just staring at a light source, it is also that light source begins moving in ways your brain expects it to move thereby giving you the warm fuzzy that all is right in the world.
