1.Flashing microtext that, when viewed with the unaided eye, appears to be part of the line design, bet under magnification is seen as a repeated pattern of words, codes or numbers.
3.Neptune was the first planet to be discovered through mathematical predictions instead of being seen, as it is too faint to be observed with the unaided eye.
4.Galileo was the first to discover, or at least record, the fact that they were actually composed of many stars so close together our unaided eyes couldn't resolve them.
5.In order to find the magnifying power of the lens, you just divide the angle subtended by the virtual image by the angle subtended by your unaided eye.
6.The original subtended angle is the subtended angle of the unaided eye – the angle between the center of the objective lens and the height of the real image.
7.Although it is possible to see Uranus with the unaided eye in good viewing conditions, it was never recognized by ancient peoples as a planet because it was so dim and moved so slowly.