2024 events

Sun 31st
13:30-14:00
Starlight Room

The Eyepieces for the Great Melbourne Telescope

Barry Adcock

Astronomical Society of Victoria, Ballaarat Astronomical Society

The Great Melbourne Telescope (GMT) was commissioned in mid 1869. The instrument was mounted in a roll-off roof observatory in the grounds of Melbourne Observatory, Birdwood Avenue, South Yarra. The telescope was supplied with seven Huygenian eyepieces providing magnifications from 234x to 1000x.

We know a lot about the history and construction of the GMT, but at this point of time we do not know who made the eyepieces, or when or where they were made. We believe that the lower power eyepieces are the largest ever made. Rather than handle these precious eyepieces we decided to make a new set of three with focal lengths of 211mm, 149mm and 105mm.

The new set were made in the author's workshop and this presentation details the design and manufacture of the new set of replacement eyepieces.

Profession: Electrical Engineer. I have studied the planets either with drawings, old film or modern digital imaging since 1960. I make all my own telescopes and equipment.