Astronomy Models
AKA: Orrery, Planetarium, Tellerium


Models which help teach about planets and the solar system.


Schools use many methods to help teach about the planets, the solar system and the moon. There are several pieces of specialist equipment available to demonstrate aspects of astronomy in the classroom.

The equipment listed below includes the most popular types of Orrery, Planetarium and Tellerium. They are available to purchase directly from the manufacturers through their website or through various lab supply company catalogues. Cochranes also stock a selection of spare parts and full instructions for all of their models.

Because schools and age groups have different requirements and budgets, different models are available to teach the different aspects of the curriculum. This guide is aimed at helping you choose the right model for you.

Overview of model types

Four types of model can generally be found:

  1. Models showing the planets orbiting the Sun. These are usually known as orreries. Key features to look for are:
    • How many of the planets are shown?
    • Does the sun light up (thereby shining light on the planets in a darkened space)?
    • How are the planets moved (manually / motorised)?
    • If motorised, do the planets move at their correct relative speeds?
  2. Models focusing on the Sun, Earth and Moon. These are known as telluria and lunaria. Some key features are:
    • The brightness of the sun lamp and extent to which it mimics parallel rays from the Sun (important for getting good demonstrations of day/night, shadows and phases of the moon).
    • The size of the Earth ? large to get good shadow depictions.
    • The Moon?s orbit ? preferably between 12 and 13 times per year and at an angle to the Earth?s orbit around the Sun. This angle is why we do not get an eclipse every month.
  3. Models showing the stars. The principle features here are the detail of the model and whether it is arranged to represent what is seen from outside the universe or inside it!

  4. Model systems showing more than one aspect (e.g. the planets and stars).

Cochranes of Oxford Products

The Helios™ Planetarium (see Fig 4)

This motorised system gives accurate demonstrations and has multiple arrangements:

The Orbit™ Orrery (see Fig 1)

For demonstrating the shape and motions of the solar system. The model includes a Sun that lights up with the planets as far as Pluto. The Earth has a moon. The planets can be moved around the Sun by hand, and the Moon around the Earth. Height: 10cm (4 inches).

Diameter of largest orbit (Pluto): 40cm (16 inches).

The Orbit™ Tellerium (see Fig 2)

A teaching model of the Sun, Earth and Moon system with a 14 page booklet.

Posters of the Sun and 9 Planets (see Fig 3)

A set of laminated posters printed to scale. Includes physical data about the planets and distances between them at the scale printed giving a real feel for the scale of the universe.

Poster sizes: heights - planets 30cm (12 inches), Sun 49cm (19 inches), widths - various.

Cochranes of Oxford model selection

The following table is a starting point to help choose the appropriate piece of equipment for you. It shows the subjects that can be studied using each model.

The Helios™
The Orbit™
The Orbit™
Scaled Posters
of the Planets
Day and night
Seasons of the year
Shadow movements
Phases of the Moon
The solar system
The scale of the solar system      
Sky at night
Zodiacal constellations

A ?Using the Orrery ? A Teacher?s Guide? is also available to download here from the Cochranes of Oxford website:
(right click and select 'Save Target As...')

This includes detailed information about the Orrery and how it can be used in the classroom. It also includes example work material for pupils.

Further information about the above products can be found by contacting:

Cochranes of Oxford Ltd. Tel. +44 (0)1993 832868.



The contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.