Astronomy and Sky Website of Martin Lewis

Content updated 12th July 2020

This is me, with my home-built 444mm (18″) f4.5 Dobsonian reflector, ‘Fossil Light’, waiting for the clouds to clear at our regular WOLAS Spring observing location at Llanerchindda Farm nr. Llandovery in Mid-Wales. This is my favourite photograph of the scope and was taken there by professional photographer and ex-WOLAS member, Max Alexander

Fossil Light was built in 1993 and for many years was used almost exclusively for visual observing and sketching of deep sky objects but since 2013 I have started using it for planetary imaging and now has become my main imaging scope, sitting atop of my home-built equatorial platform. Untracked visual observing is done on visits to dark sky sites like Mid-Wales or the Autumn Kelling Heath Star Party in North Norfolk, whilst imaging is carried out in my back garden in St.Albans, Hertfordshire. At home I also use my smaller 8.75″ Dobsonian particularly for daytime imaging of Venus and Mercury.

Fossil Light is named in recognition the light from distant galaxies which started out on its journey to us many millions of years ago and which in essence is the fossil record of something that existed millions of years ago. The name was taken from one of the beguiling Cosmic Gnomes on the Tower of the Ecliptic (Marina Towers) on the waterfront at Swansea, which was used as an observatory until 2010 by the Swansea Astronomical Society.

The mechanics of Fossil Light were built entirely by me over a period of 3 years in my spare bedroom when I lived in Colindale in North London. The 450mm Suprax primary was made by Jon Owen and the 83mm secondary was made by David Hinds. The scope was finished in 1996 and cost £3000 in parts, taking me some 3,000 hours in total for design, manufacturing and testing.

The telescope has featured in a BAA journal (Journal of the British Astronomical Association, vol.109, no.5, p.247-256) – please click below to download this article, which is reproduced by kind permission of the BAA. The scope has also featured in Sky and Telescope articles written on the optimisation and understanding of altitude and azimuth bearing friction in Dobsonian telescope (S&T Oct. 1999 and Oct. 2003 issues).

You can also download a fully-illustrated 8MB pdf presentation I have made about the making of Fossil Light by clicking the button below.

You can see more pictures of the scope in action on my home-built equatorial mount on the accompanying page.

Kit of component parts for Fossil Light on lower patio at my home in St.Albans