This kit assembles to make a working model of the inner Solar System including Mercury, Venus and the Earth and Moon. It shows the relative movements of the planets around the Sun, and the Moon around the Earth. The Sun contains a light source which can be used to demonstrate how night and day, the phases of the Moon and the seasons are produced. This is an excellent model that can be used for personal amusement or as an aid to teaching.
Mechanical planetaria were already known in ancient Greece, though the planetary orbits with their loops, that the Ptolemaic world model constructed around a stationary earth at its centre, most likely cannot have been replicated mechanically. The most famous example is the Antikythera mechanism, discovered in a shipwreck, which was much like a calculating machine. It is said that Archimedes, too, was able to demonstrate mechanically the orbits of the Sun and Moon.
Almost all of the mechanical planetaria we know are based on the ideas of Nicolaus Copernicus (1473 -1543), who regarded the Sun as the centre of the world. He proclaimed that the Earth does not remain in place but rather moves in three ways: it revolves once in 24 hours, orbits around the Sun once per year on a circular path and, in a third movement, turns its axis in such a way that it always points in the same direction and not towards the Sun. Despite heavy resistance from the church this world model continued to spread and, through improvements made by numerous scientists, evolved into the generally accepted scientific world model of today. One of these scientists was Johannes Kepler, who discovered the elliptical nature of the planetary orbits.
At the beginhing of the 18th century the Earl of Orrery and other English aristocrats asked watchmakers to manufacture crank-driven mechanical models of the planets, which are called orreries since that tirne. One of the largest and most famous movable planetariums was built; by the Frisian Eise Eisinga in the years 1774 to 1781 in the town of Franeker; where it is still exhibited.
Today the, name "planetarium" is mostly used for projection planetariums like those that were first constructed by the Zeiss optical company in Germany at the beginning of the last century. These project the stars onto the inside of a large dome.
The AstroMedia* Copernicus Planetarium stands in the tradition of the mechanical, crank-driven planetary models that are exhibited by selected museums as masterpieces of the watchmaking and precision engineering arts. Its simple drive belt design, the robust cardboard construction and the affordability of an assembly kit make this interesting and instructive device available to a larger public once again.
Things Needed For Assembly:
- Cutter knife or scalpel with a slender blade tip.
- All purpose glue. This may be used for all parts. Solvent-based glue has advantages over water-based glues: it will not warp the cardboard, dries much faster and adheres better to the lacquered cardboard surfaces. Tip: you may need several tubes/bottles.
- Instant adhesive with a comfortable drying time (meaning: not too fast) for glueing cardboard to plastic or metal and, should this become necessary, for constructing NBR-rubber drive belts. Please pay careful attention to the handling and safety precautions particular to instant glues!
- Quick-drying white wood glue - this can be used instead of all purpose glue for the larger parts, but does not work so well on lacquered surfaces. Drying times will be much longer, but in return you will get stiffer bonds.
- Fine sandpaper for sanding off projecting cardboard edges.
- A cutting board made of thick, completely flat cardboard, wood or plastic material. Best are the "self-healing" cutting mats whose cuts close by themselves again.
- A ruler or set square, for cutting, measuring and checking right angles (for this purpose the right-angled corner of a sheet of paper will also do).
- A pair of pliers or a wire cutter for shortening the nails, if necessary. For holding or pressing small parts, tweezers or clothes pegs can be useful.
- A steel pin and a sewing needle, or, even better, a 1 mm hand drill for widening the indicated holes in the steel pin bases to a diameter of 1 mm.
- Sellotape for reinforcing cardboard surfaces.
- A round wood file will be of good use for widening the holes in the grey cardboard discs.
- Light, non-resinous machine or silicone oil (do not use food oil!) against squeaking noises where synthetic discs move on wooden surfaces.
OPTIONS: The word OPTION and italics mark assembly sections that you do not have to carry out, but may. For these steps you will need:
- A piece of plywood or similar material, about 21 x 21 cm, for reinforcing the base, if the orrery needs to be prepared for regular use, for example in schools.
- A thick black marker, white paint or correcting fluid, if you wish to colour the edges of the grey cardboard.
- Opaque colours, coloured felt tip pens, correcting fluid, if you wish to paint the wooden globes representing Earth, Moon and planets.
This kit contains:
- Die-cut sheets size A4: 6 sheets of unprinted grey cardboard 1.13 mm (sheets 1-6), 12 sheets printed offset cardboard.5 mm (sheets 7-18), 1 sheet printed offset paper.13 mm (sheet 19).
- Cardboard and hard paper tubes (axles and shafts): One piece 100 x 12 x 10 mm (length x outer diameter x inner diameter), one pc. 27 x 8.8 x 7.5 mm, one pc. 38 x 6.5 x 5 mm, one pc. 14.5 x 34 x 32 mm.
- Round wooden sticks (axles and shafts): one piece 8 x 240 mm (diameter x length), one pc. 4 x 70 mm, 2 pcs. 4 x 56 mm, one pc. 4 x 38 mm.
- Plastic bearing discs with hole (axle and shaft bearings): 6 pcs. 14 x 4.1 mm, 2 pcs. 20 x 8.2 mm, 2 pcs. 20 x 8.6 mm, 2 pcs. 25 x 4.1 mm, 2 pcs. 50 x 29.3 mm, 2 pcs. 55 x 34.3 mm.
- Spring steel pins (mounting for Moon and planets): 4 pcs. 1 x 43.5 mm.
- Wood globes (Moon and planets), pre-drilled: 2 pcs. 16 mm diameter, one pc. 6 mm, one pc. 4.5 mm.
- Brass tube (Earth axis bearing): one pc. 1.5 mm outer x 1.1 inner diameter x 10 mm length.
- Neodymium magnet (Earth rotation drive): one pc. 15 x 2.5 mm.
- Silicone tube (Earth rotation drive): one pc. 2.8 mm outer x.8 inner diameter x 12 mm.
- NBR-rubber drive belts: one pc. 4 mm diameter, 5 pcs. 2 mm diameter.
- Ferrite magnets (Sun mounting): 2 pcs. 8 mm diameter x 4 mm
- LED glow globe (Sun): one piece 45 mm diameter.
NOTE: The blue cover is in German but the instructions inside the package are in English.
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