In "As You Like It" Shakespeare wrote the lines spoken by Lord Jaques ".... one man in his time plays many parts, his acts being seven ages....". Knowledge of the number seven would get you a long way in the Tudor era. There were seven musical notes, seven days of the week, seven churches mentioned in the book of Revelations, there were the seven metals known to the ancients (Gold, Iron, Tin, Lead, Silver, Mercury and Copper), seven colours of the rainbow, seven stars in the Pleiades, seven mortal sins, seven wonders of the ancient world and seven days of creation (well six working days and a rest day to be exact). There were also seven archangels each one associated with a day of the week. In 1917 Sergei Prokofiev composed a cantata called Seven, They are the Seven based on a cuneiform tablet found on a 4500 year old Akkadian Temple. The seven figures on the tablet are evil spirits. Prokofiev's composition is rarely performed as it requires a huge orchestra and choir and lasts for only seven minutes. It is also quite difficult to listen to at first but bears rewards on repeated listening. The solo tenor and choir repeat "Sem" (Russian for seven) over and over again in a hypnotic manner that builds up and leads to a climax. The cantata has been described as Russian Primitivism and also as Neo-formalist. It can be found on You Tubehttps://www.youtube.com/watch?v=IdtHOOxPgCo
The other seven that everyone knew was the seven celestial globes which rotated around the Earth namely the Moon, the Sun, Mercury, Venus, Mars, Jupiter and Saturn. The Tudors believed in a correct cosmic order and if matters behaved well in the cosmos then things would be orderly on Earth. Eclipses, comets and supernovae were interpreted as harbingers of chaos and disorder. From the Bible the number seven has always been connected with something complete or properly finished. The seven days of creation, there are seven branches on the tabernacle lamp stand, Naaman the leper is told to bathe in the Jordan river seven times in order to be cured. Joshua is told to march around Jericho seven times with his men blowing seven trumpets. The number seven is associated with and was understood to refer to completion of a divine mandate. There are seven Noachian precepts that humanity is obliged to observe to prevent the future destruction of the world.
Shakespeare uses the phrase 'seven years' a total 17 times in his plays to signify a completed period of learning, journeying, longing, studying, incarceration or just plain waiting. Shakespeare uses the phrase 'eight years' only four times and 'six years' 4 or 5 times (on the fifth occasion it is six or seven winters by Isabella in Measure for Measure II,1) Anne Hathaway his wife was seven years older than Shakespeare as well. To the Tudors seven days, weeks, months or years or represented the ordered completion of one cycle of events and the start of a new one. There were seven celestial orbs known to the ancients but then in 1610 Galileo found four more. Its hard for us to imagine the profound effect that this would have had on Jacobean society. This would have brought the number of celestial orbs up to eleven! It was understood that the Moon was created for the benefit of the Earth's inhabitants but what benefit could there be from four moons circling around Jupiter? These moons existed for Jupiter's benefit not for the Earth's benefit. Galileo even throws down a gauntlet of challenge in Sidereus Nuncius and explains exactly how to build a perceptillum (telescope) and states that he will submit to the "judgement and censure of right thinking men". One astronomer even claimed that he had seen the Jovian moons before Galileo (Simon Marius of Ansbach). Possibly he had but he did not publish first and his notebook started one day after Galileo's!! By autumn 1610 the presence four Jovian moons had been verified and were accepted as a problematic astronomical fact.
In late 1614 Ben Jonson wrote his masque Mercury Vindicated from the Alchemists at Court which was performed on Jan 6th 1615 and then again on Jan 8th 1615 at the King's specific request. In this humorous masque Jonson writes that "and there are more orbs and planets are than seven". Could Jonson be referring to the discovery of the four moons of Jupiter by Galileo? The secret was well and truly out and the cosmos was no longer the safe secure well ordered place it was under the Tudors.
I saw Jupiter's moons myself at the age of eleven with telescope that I was bought as a birthday present and was barely more than a toy with a rickety tripod. With a decent telescope (an 8" reflector with a motor drive) and live image stacking software it is quite easy on a clear night to get excellent images of Jupiter and the giant planet's four moons.