30+inch+F3+Test+Rig

The 30 inch F3 mirror required a new mirror cell for the test rig telescope. In addition to the upgrade of the mirror cell, the test rig tube has had some additional modifications including aluminium tubes.

The mirror cell was designed in PLOP and in SketchUp-Make. The mirror cell is now a balanced design and uses PTFE lined spherical bearings.

The stainless steel lateral support wire runs through the centre of gravity moves with the support frame so that its position on the edge of the mirror does not alter during collimation.

The cell is designed to a balanced system, so that no matter what gravity vector the cell is moved through the 'triangles' do not move and put unequal load through the back of the mirror.







The support frame is made of steel and is welded 'C' channel. Drawing templates were used to align parts before welding.











The 30 inch F4.6 mirror in place for testing. The lateral wire is to be adjusted to match this mirror for testing on sky. This will then be adjusted again for the 30 inch F3.



Below is the test rig with the poles for the 30 inch F3 Telescope test rig at first light on the 30th June 2015. Mirror is getting closer to being completed and Saturn and the Moon looked quite good even with the mirror 1 wave PV on the wave front still needing correction.



The image below shows a temporary modification to the test rig by removing the secondary and adding a focuser for visual and CCD star testing to verify the primary without muddying the waters with the secondary.



Another variant on te test rig for testing was to fold the telescope into a 'lowrider' design. This uses a 10 inch flat (that is VERY flat) for visual testing on sky. The flat we have at the moment (August 2015) is not that flat. We are working on either getting an alternative or making one ourselves. The 'lowrider' design means the eyepiece is less than 5 feet from the ground. No ladder needed....but it is a little uncomfortable to use to be honest.



Image below is of the test rig tidied up just before being displayed and used at the 2015 September Kelling Heath star party.



Image below is of the test rig tidied up for the September 2015 star party at Kelling Heath.