No, New Moon is invisible full stop, barring Earthshine as I mentioned. There is no "in terms of astronomy". If you're using the term to mean something else, use another term; because in this, as in so many other things, you are factually incorrect.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'
