Aneio, the site you are quoting from says that the secondary blind spot can see nothing in very low light.
Read it again. That's what it says.
Let's see if I can find you some more information...
Ah... here:
From Sport Pilot:
"The "Night Blind Spot" appears under conditions of low ambient illumination due to the absence of rods in the fovea, and involves an area 5 to 10 degrees wide in the center of the visual field. Therefore, if an object is viewed directly at night, it may go undetected or it may fade away after initial detection due to the night blind spot."
http://www.esparacing.com/sport%20pilot ... 20spot.htm