An orrery is a mechanical portrayal of the solar system which shows the relative movement of planets to the sun and each other. When you see an orrery for sale you may want to compare it to others on the market to assess its actual value. There are many factors to take into consideration and for true comparisons they should all be looked at.
Obvious factors are the material it is made of, size and its general condition, both in looks and in movement. The type of orrery is also a factor as their are many different versions. The amount of planets and their moons can vary tremendously and therefore so can the complexity of the item itself.
Built originally as a scientific piece, these amazing items can clearly show the movement of each planet and moon. It is worth remembering that at the time some older ones were built, not all the moons or even planets we know of now, were recognized or known.
Originally they were called planetariums but that word has now become more widely used to describe the light shows in large domed rooms, which depict the night sky. Now they have many names which describe ones with certain groups of planets. So it might be worth knowing which style you prefer to help cut down your search.
The idea is that the mechanism shows the movement of moons around planets and planets around the sun. They also includes the spin of each planet and moon and the tilt of each on their axis. This makes them very complex and building them takes a lot of skill.
As it is geared for each planet to move correctly, then it also shows how the planets become quite separated at some times, while at others they are quite close. It can be clearly seen when moons cast shadows on their planets and when eclipses are to happen. They are often driven by clockwork so that you can watch the cycle unfold.
When you consider that both Jupiter and Saturn have over 60 moons each, a fully detailed version would be a very large and expensive item, so only certain features are depicted in different versions. They are usually not perfectly accurate either with orbits being in whole rotations while true orbits are not that accurate. The vast differences in sizes of the planets and their orbits also means that they are rarely built to scale..
When you find an orrery for sale now, you should now be able to identify exactly what you want. Bearing in mind the limitations of these wonderful items you can decide on size, material and complexity to fit your home and your wallet. Knowing that the decision you make will be informed and the item will be more than a novelty ornament.
Obvious factors are the material it is made of, size and its general condition, both in looks and in movement. The type of orrery is also a factor as their are many different versions. The amount of planets and their moons can vary tremendously and therefore so can the complexity of the item itself.
Built originally as a scientific piece, these amazing items can clearly show the movement of each planet and moon. It is worth remembering that at the time some older ones were built, not all the moons or even planets we know of now, were recognized or known.
Originally they were called planetariums but that word has now become more widely used to describe the light shows in large domed rooms, which depict the night sky. Now they have many names which describe ones with certain groups of planets. So it might be worth knowing which style you prefer to help cut down your search.
The idea is that the mechanism shows the movement of moons around planets and planets around the sun. They also includes the spin of each planet and moon and the tilt of each on their axis. This makes them very complex and building them takes a lot of skill.
As it is geared for each planet to move correctly, then it also shows how the planets become quite separated at some times, while at others they are quite close. It can be clearly seen when moons cast shadows on their planets and when eclipses are to happen. They are often driven by clockwork so that you can watch the cycle unfold.
When you consider that both Jupiter and Saturn have over 60 moons each, a fully detailed version would be a very large and expensive item, so only certain features are depicted in different versions. They are usually not perfectly accurate either with orbits being in whole rotations while true orbits are not that accurate. The vast differences in sizes of the planets and their orbits also means that they are rarely built to scale..
When you find an orrery for sale now, you should now be able to identify exactly what you want. Bearing in mind the limitations of these wonderful items you can decide on size, material and complexity to fit your home and your wallet. Knowing that the decision you make will be informed and the item will be more than a novelty ornament.
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