Jack Ells’ Rocking and Rolling Observatory

Plinth Dates: 16-18 September 2011

Jack Ells’ Rocking and Rolling Observatory

Observatory model by Jack Ells: wood, balsa wood and art construction card.

A 1-in-8 scale model of a unique astronomical observatory. The telescope (a 32-cm Newtonian reflector) sits in a separate, cold compartment while the observer works in a cosy room.

The observatory rotates on a circular track. A complex motorised framework in the pit below rotates about the polar axis, tilting the observatory by ±5o (!), to follow the stars automatically for 40 minutes.


    Oblong, wooden telescope tube
    Insulated cabin walls
    Adjustable observing step
    Hand-cranks conveniently nearby control observatory
    ‘Norton’s Star Atlas’ book
    Observer’s notebook with drawing of Jupiter
    Picture of Royal Greenwich Observatory
    Moon map
    Observer’s beer!

The telescope, built by engineer and amateur astronomer Jack Ells, operated very successfully for many years. The telescope was originally built as an alt-azimuth instrument. The motorised, equatorial sub-frame that made the observatory tilt was added some years later.

The observatory was described in Peter L. Manly, Unusual Telescopes (Cambridge University Press, 1991).

Contributed by Peter Ells