Amateur astronomy is sometimes all about equipment. I’ve been using the same equipment for a number of years now and from what I read these days, my telescope is not available anymore. I use a Takahashi FS-102, a Losmandy G11 with Level 4.1 Goto Gemini Control, a variety of eye pieces and a Canon Rebel XT which I modified for full spectrum Photography. I just recently purchased a Guide camera which I will be using with PHD guiding software. I’ve successfully used a Philips SP900C Web cam in the past, but the sensitivity of the chip in this camera is really not enough to pick-up dim stars. This is typically what one needs for guiding near the object of interest. My guidescope is Meade 3″ F11 Achromat refractor, and with this kind of focal ratio, I expect to get excellent guiding with the combination setup. This is a fantastic setup and is kind of a workhorse these days with the mirror manufacture I am performing. The 16 inch will be placed into a truss design Dobsonian scope that I have designed and built over the years from as much scrap wood and metal and plastic parts at possible.
This first image is the completed scope at the RTMC in San Bernardino in 2006. Some details of the scope, the secondary cage, the mirror cell, which I designed and fabricated from steel bars and angle iron with no welding and all mechanical fasteners. the Mirror box is made from 1 1/4″ pressed wood from an old office desk I recovered near an abandoned commercial office area. The truss poles are thin aluminum shower curtain rods from a building supply store (the Orange color place), the secondary cage is made from 3/16″ panel ply that I cut into two inch wide rings using a router. Then using pine 1″x 2″ cut to length were fashioned into supports between rings. 1/64″ plywood veneer was glued inside the cage which made it rigid enough to sit on! (althought I did not test this), and the spider is made from steel strapping found at a construction site fused to hold together a shipment of lumber. Holes were drilled to lighten it. 1/4′ aluminum rod was threaded with 1/4-20 on one end for and slotted at the other. A small hole was drilled in the end through the slot and the end of each spider vane and positioned into the secondary cage. Holes were drilled at four locations on the cage, rod fed through, and wing nuts used to position the secondary mirror in the center of the optical path. This set-up allows adjustment of the cage laterally if necessary. The secondary mirror holder is made from PVC pipe slotted at one end and a larger pieice cut at 45 degrees and glues to a plywood oval. Three machine threaded screws with threaded flush anchor nut were are then mounted with spring in between to allow adjustment. A couple of things I did purchase however, were the secondary mirror, the low profile focuser, and teflon materials for bearings.
This scope was built about twelve years ago, and needs some improvement, but still works pretty good. The truss pole anchors are made from laminated ply glued together and then drilled and sanded to match the angel the truss pole makes with the mirror box. The balance point of the scope can be adjusted by using steel bars that are attached to the secondary cage or removed as necessary if a large or heavy eye piece is used for viewing. I could describe more detail, and the scope was a challenge and a pleasure to build. One day I’ll double the size of my next project, but for now, still satisfied with this one, and the effort it took to get here!