Check the squareness and clamp the whole unit for 24 hrs as recommended Stellafane Cradle. To make the azimuth bearings, cut the PTFE sheet into three 25mm square pads (unless you are using ‘Slide Glides’); secure these in the 1.5mm pilot holes in the rocker box base (see Diagram 1) using No 6 ¾-inch screws. Dobsonian telescopes offer big thin mirrors with stable, inexpensive altazimuth mounts. $21.00 $ 21. Make sure the product you use is intended for outdoor use. I was going to use the album (in fact I purchased Kenny Rogers Christmas Album from Ebay for $2.00) but decided to use an inexpensive laminate (Formica Brand Laminate 30-in x 96-in Ouro Romano-Etching Laminate) from Lowe's because the teflon sliders could be spaced farther apart. Mark the centre of the two side panels you produced in Step 5 with lines from opposing corners again to form a cross at the centre. I attached 5" diagonal triangles just below the handle for added strength with wood glue and wooden dowels. Drill pilot holes for the cut-outs then re-position the nail in the jig and rout out the two holes. Sand all the components and round the corners of the two bases. Drill the threads out of one T nut to form a smooth bearing and insert both T nuts. All a person needs to do is grab the scope and move it in the right direction. Wow looks really nice. For the altitude bearings, cut four rectangular pieces of PTFE 25mm long by the width of the rocker box sides, then drill and countersink them. Collimation Spring Kit for Zhumell 12" Z12 Dobsonian, FZ323. To begin the build, enter the nine dimensions required in the yellow boxes of our Calculations spreadsheet. Cut the edging strip to the correct width with scissors and attach it with impact adhesive to the perimeter of the altitude wheels, securing the ends with No 6 ¾-inch screws and cup washers. Jim at ScopeStuff happened to have one last bit of ¾" by 48" bearing strip left. Using a clamp, press six ¼-20 Tee Nuts into each hole. I then repeated this procedure with the other bearing. The secondary mirror mount is unusual. As recommended by Stellarfane, I used three hockey pucks for the feet as they are weather proof and raise the ground board enough for the pivot bolt to be secured on the bottom. Adhesives – Both PVA wood glue and epoxy resin are needed. Easy assembly, all parts included. The width is critical and needs to be cut with care so your cradle can swing freely: Rocker Box Front Width = Cradle Width + 1/8 inch Clearance Gap + (2 × Side Thickness). Gently lower the altitude wheels into the bearing ‘cups’ to complete the assembly. In this section we will show you how to build a complete Dobsonian Telescope. This method makes a perfect circle where the edges are already squared off. This number was used to make sure the rocker box has adequate height so that the telescope can point at the zenith without colliding with the bottom of the rocker box. Mark the centre of the side panel sheet (the long rectangle), drill a pilot hole, then move the nail in the router jig to position ‘b’ and cut out another circle. For this work I was fortunate enough to have a router to use. This jig is vital to turning the square altitude-bearing wheel ‘blanks’ into circles. I've been there. This time the circle will be incomplete, leaving you with two rocker box sides with one scalloped edge. Finally I paint the stand with with outdoor black paint. The last step is to build the mount. I then sealed the board with high gloss polyurethane. Carefully mark the centre of each square altitude-bearing wheel blank by drawing a line diagonally from opposing corners to form a cross at the centre. There are a lot of options for the ground board (see Stellarfane), however, I chose the easiest construction especially since I had cut the board to size already when I made the rocker box bottom. Frustrated with the high cost of a proprietary Go To, the author developed a free, open source, DIY option, rDUINOScope Boiana.. rDUINScope Boiana is an open source Go To unit. Reply If you have a 150 mm F8 mirror, a 200 mm OD tube is needed. When the glue has dried, sand all the surfaces including the altitude wheels and the retainer discs. Replace the router’s foot with this jig, then push a 2mm round nail through position ‘a’. What I ended up doing was installing knobs on the remaining four guide bolts which allowed me to raise the pressure plates evenly and allowed enough room to fit the optical tube though the cradle. I applied a second coat to the bearing edge as it is very porous. Telescope – This project assumes that you own or are going to acquire a Newtonian reflector tube with an 8-inch or greater aperture, as well as suitable tube rings and a pair of dovetail bars. After cutting this to size I applied contact cement to both surfaces according to the directions and let it dry. As recommended by Stellafane I put #6 - ½ inch stainless steel pan head screws at each end of the bearing for extra security. We chose to use cheaper ‘Far Eastern’ plywood and give it a painted finish. Ensure the optical tube will fit through the box and the Pressure plates fit into the box and that the circular cut triangles match up with the optical tube (dry run). As a final option, you can use the swing of the telescope to determine the position for the attachment of a bracing bar. #rDUINOScope is an Open Source, Arduino Due based Telescope Control System (GOTO). Finally I checked to make sure the rocker box rotated smoothly on the ground board. I mounted the bearing by screwing #6 × 1 inch wood screws through the cradle from the inside.