First check your state regulations, make sure you can use a light, like here in Georgia, you can use a light as long as its not over 6 volts. Get one of the preditor lights that have mounts that slip over your scope, they have adjustments that will direct the beam to line up with your cross-hairs, they also come with a red lens, spend the little extra money and get one with a 300yrd. beam, when you have the red lens down it cuts down on the yardage to about 200 to 250yds. I dont use the lens much for coyotees, the white light doesnt seem to effect them so much around here, youll just have to see what works for you. As far as hunting them by day or night, they generally rome and hunt for food at night,you can also get good action around sunrise and sunset,if you happen to hunt around any chicken houses, just after they spread the chicken droppings on the fields you can pretty much hunt them all day long for three to four days.