TEN INCH F/8 NEWTONIAN REFLECTOR

Construction of this telescope was begun in 1992. Designed to be a semi-portable instrument, it is shown above on its traveling amount, a University Optics German equatorial with 1.5" solid shafts and driven by a 9" Byers drive. It also has a large, roll-out, English cross axis mount that sits in the garage for home use and can be easily moved out onto the driveway or front lawn. Construction is of plywood and Sonotube covered with polyester resin sanded and then painted. The tube separates in the middle and is held together with four bolts with wing nuts. Breakdown is quick and easy and this 8 foot long tube travels easily in two, four-foot sections. One of the features of this design is the partially open lower box containing the mirror and a rather substantial covering for the diagonal. The box is so designed so as to afford only enough protection to inhibit dewing of the primary mirror. The same rationale, dew reduction, was behind the longer than typical top end. The top is constructed of Sonotube and rotates within plywood rings. 

Originally the telescope was a solid tube design. This proved not to work well at all. The telescope suffered from tube currents and took a great deal of time for the optics to settle down. It was also difficult to use in certain attitudes. Subsequently the top half of the tube was discarded (it had always been designed so as to be broken down into two pieces) and a new rotating truss top end was built. At the same time the solid box lower end was cut open into its present form. The improvement in performance was amazing. The telescope would now completely stabilize within two hours of setting up and the tube currents were gone. The last touch was the installation of an exhaust fan at the bottom end. Even with the open truss design, the exhaust fan has proven to be invaluable in producing an instrument which performs to very high standards. With the use of the exhaust fan the mirror will now settle down completely in 1/2 hour.

I have to admit that I am not much of a fine finish woodworker type. However, I do enjoy designing and making light, serviceable and solid telescopes out of wood and cardboard. These materials are easily obtainable and easy to work and, if treated (coated) properly with modern resins, produce a light and sturdy housing for an optical system, quite superior to metal in many ways. Mostly, my techniques involve tacking pieces together with Elmer's glue and then painting the entire structure with polyester resin. Polyester resin is very much cheaper than epoxy resin, dries relatively quickly and sands to a very smooth finish suitable for painting. People have no idea what the telescope is made out of. A telescope or any object so constructed will be extremely rigid and strong and impervious to moisture. Essentially, joints do not exist. It just becomes one solid, integral mass. If you take a hammer to it, it breaks everywhere but the joints.

The entire rig. Waiting for the Jupiter impacts in July, 1994.

Tube structure. Note point of separation and wing nuts. Also note mirror at base without mirror clips.

Rotating Top. This photo and one above show how the Sonotube fits into the plywood frame.

Underside of tube showing attachment to equatorial mount. The University Optics mount has worked rather well over the years. It required some modification in the form of larger bolts here and there, but is basically a very sturdy mount.

Side of two and mount. Once again, note where two plywood pieces come together at the point where the tube separates.

Bottom end of tube. Square plywood bottom of cell unbolts for removal of cell.

Mount base. The University equatorial mount fits into a 4"diameter  steel pipe. Aluminum legs were also purchased from University Optics. I bought an extra leg. This added considerable strength and rigidity as well as making amount easier to adjust

Tube attached to the rollaway English cross axis mount. No room for the car! - oh, well.