DIY Budget Guide Scope

To make a guide scope for my auto guided barn door tracker on the cheap I decided to use only materials I had laying around, this included an old Chinon 135mm f2.8 SLR lens, a Trust WB8200 webcam, an old project box recycled from another project and an 30mm M42 extension tube + M42 lens to Canon EOS adapter.

To make the Guide scope I cut a hole in the front of the project box just large enough for the Canon adapter to snugly fit, I then drilled two small holes in either side of the adapter so I could pass through a couple of M3 sized bolts, these along with a thin coating of Epoxy resin is what secures the lens adapter to the box. The next step was to dismantle the webcam and remove the lens from the webcam and the front half of the webcam cover, this was reasonably easy to do by just removing a few small Phillips screws and unscrewing the lens, on the rear of the webcam cover there are four small tags to which I applied a small amount of Epoxy resin and stuck this to the back of the Canon adapter inside the project box, making sure the imaging sensor was central and allowed to set overnight, the same was done with a 1/4-20 T nut on the bottom of the box on the inside to enable it to be mounted on a ball head.

The Guide scope mounted on my dual axis barn door tracker, along with the main imaging camera, the whole set up is very sturdy.

To achieve focus it was necessary to place an extension tube between the Canon adapter and the Chinon lens, the guide scope works fine for it's intended purpose and I'm pleased with the end result. The Trust WB8200 Webcam that I used can be replaced by a Trust WB5400, with the use of some software called WcCtrl it will allow exposures of 1 second.