1. The Controversy on the Comets of 1618
2. “Let us cause our vision to pass through … a tiny opening which we may leave between the palm of our hand and the fingers, clenching the fist and bringing it to the eye, or through a hole made by a fine needle in a card” (Galileo, Dialogue (trans. Drake S., Berkeley, 1953), 337).
3. “It is necessary to prepare quite a perfect telescope which will show all objects bright, distinct, and free from all haziness, while magnifying them at least four hundred times and showing them twenty times closer” (Drake S., Discoveries and opinions of Galileo (New York, 1957), 30).