The 16 inch F4 telescope in the run off roof has been upgraded to a 16 inch F3. The whole tube assembly has been removed and the mirror is now used in a new 16 inch F4 Dobsonian for Geoff Regan.

The telescope tube was replaced as a technical demonstrator for future larger F3 designs. In particular the 30 inch F3 prototype. This deign will be a future product of Thomson Telescopes when all outstanding technical issues are resolved.

The 16 inch F3 mirror was made from Supremax 33 and supplied generated as fine annealed generated blank from Reginato in Italy.

Dave Owen's notes are here for the manufacture and testing of the mirror.

The mirror and telescope tube have been completed in 2014 and installed into the observatory.

Image of the original 16 inch F4 is below. This had a 5 inch round flat mirror bringing the light path back into the CCD in the middle of the tube. Alignment was difficult and re-configuration of the camera would not be easily possible.


Image of the replacement 16 inch F3 tube during installation and re-wiring. The is a 5 inch elliptical flat folding the light out through a 3 inch focuser that will be motorised.
A filter wheel will also be added. A flat light box can now be installed in front of the tube when parked, similar to the wide field telescope.
The tube does not look as nice but performs very well as it is better protected at stray light and is easy to work on and even look through!!

16 inch F3 polishing and figuring