I unscrew the aperture, like mspaci mentioned. It does cut down on accuracy, but I would personally feel comfortable shooting a deer at 50 yds with no aperture and in low light, I wouldn't take a shot much farther than that anyway. If it is too dark for the peep sight with aperture installed, then it is too dark for anything except close range work, for me anyway, YMMV depending on eyesight and terrain, ect. Some time at the range, take the aperture out and give it a try. It may or may not work for you, but it is definitely worth a try.