Tools – Jigsaw, router, hacksaw, drill and bits, plane, spanner, Allen key, screwdriver, Materials – 1,200x600mm sheet of 18mm plywood (this is enough for parts one and two of this project), 1m length of 30x30x2mm aluminium angle, 1m length of 12x2mm aluminium strip, A3 sheet of thin polycarbonate plastic or similar, 600x40x30mm offcut of wood, Sundries – Eight 608ZZ skateboard/roller blade bearings (22x8x7mm), eight M8x25 socket head screws, eight M8 washers, 16 M8 nuts, woodscrews, wood glue, double-sided tape. This two-part project aims to deal with this inconvenience. The mount is only one of its many problems. Now we’ll show you how to complete and motorise the Dobsonian equatorial platform. Why Build a Dobsonian Telescope Yourself? Setting Circles. You, too, can avoid astronomical costs by watching stars through a tricked-out cardboard tube. The DC motor you need to buy should come with a built-in gearbox with a published speed of 10rpm or less. Skywatcher 10 inch Dobsonian. You can find the centre of gravity of the mount box by balancing it on its side, and the combined centre of gravity will lie between the two. pads and textured laminate) and will provide details on where to buy Mark around the bearings and arm support to draw a suitable shape for the base. provide many dimensions as formulas with the specific of your tube Short pulses are sent to these motors by a special controller to precisely control the motion of the scope. They provide large apertures for a reasonable price and as such are suited to observing faint, deep-sky objects. Once you have assembled all your parts you will need to spend a little time adjusting your platform until it runs smoothly and checking that the north bearings make good contact, as these guide the telescope’s movement. If you find this too fiddly, you can buy toothed belts with matching small gears instead. The Kid Peek Telescope. curved parts when absolutely necessary. I must admit I cheated and bought the focuser off the Internet. The Springfield Telescope Makers, Inc. The platform is constructed from 18mm plywood and the bearings are 608ZZ skateboard bearings, which are inexpensive and readily available. Assemble all the parts and check to see everything is moving freely and the gears are engaging. It is possible to do a good job by hand, but if you have access to a router then generating accurate profiles is easier. When the power is on, these motors turn fairly constantly, but quickly. Commercial motor drives for telescope mounts are available for projects like this, but they can be expensive. Our spreadsheet calculator (also at the link) once again comes to the rescue when it comes to working out gear ratios so all you need to do is input your values and experiment with the numbers until the ratios match your needs. Manual Dobsonian . surfaces should be sealed except those that will have laminate glued Using moments, you can calculate the exact position. Monday, 2013-Feb-11 07:55:01 -0500, Our Dobsonian Mount with Adjustable Cradle. dimensions such as the tube length below the balance point of the This Instructable describe the planning, design, and par… Dobsonian Master Index, Page last revised on Shaping, Drilling & Sanding page, which gives general advice on Binocular Chair . the finish, usually when that component of the mount is complete, or mount with a clear satin polyurethane (left over from refinishing We will therefore Since we know the radius of our north segment (from Part 1) we can work out the length of a 15° section of the circumference. each part is completed; we will just tell you it is time to apply We used a home-made gearbox along with the gearbox built into the motor, and an off-the-shelf controller to modify the output speed to suit our needs. a completed and functional Newtonian telescope in hand; critical After separately weighing your telescope and mount/base, balance the base on an offcut of tube to find its centre of gravity. In 24 hours this is only slightly more than one full revolution (360°), so in one hour the platform should turn 360/24 = 15°. tube. Cutting out the plywood parts is quite straightforward, but the curves do need to be smooth. The plywood Dobsonian mount is simple to build and very functional. Model "22X4" Cheap and Simple. Red Dot Finder Mount . Cradle If it is too far above or below, the motor may struggle to drive the platform effectively. Do not try to build this mount without Assemble box with wood glue and #17 1¼" or 1½" wire brads (four per side). to them - the glue will stick better to bare wood. from the tube down. Ascertain best position for the south bearing and fix it with a central pivot screw. See more of his work at buttondesign.co.uk, How to photograph the Moon with a digital camera. Dobsonian telescopes are popular instruments. Use a strip of modelling clay and the output gear to create a profile for the rack. Use the spreadsheet calculator in the downloadable materials to select appropriate gears. The segments are arranged so that this centre of gravity lies on the axis of rotation. for a small (12 inches or less primary mirror) Newtonian optical Use M3 screws and nuts to hold it all together. Well, I recently (as of November 2001) motorized my Dob. Don’t cut the segments away from the board until you have finished smoothing the arcs. Using a clamp, press six ¼-20 Tee Nuts into each hole. These are the easiest shapes to generate and provide good results for medium-sized scopes – our example project is based on an 8-inch, f/6 Dobsonian. 13.1" Twin Tube Telescope . Tools – Jigsaw, router, hacksaw, drill and bits, plane, spanner, Allen key, screwdriver, hot glue gun, file, Materials – Remainder of 18mm plywood and 30x30x2mm aluminium angle from earlier in the build, Sundries – Modelling clay, worm, wheel, small spur gear, suitable axle (4mm rod), three M8x75 coach bolts with six M8 nuts, motor/gearbox (ours was 12V and 10rpm output speed), DC motor controller, M3 screws and nuts, M6 screw, Nylock nut and washers, Finish – Preservative wood stain or paint. Once satisfied, cut out the segments and remaining parts. Binocular Mount . They use sophisticated stepper motors, which move by very small, predictable increments. In this section we will show you how to build a complete Dobsonian Telescope. If you have a router you can attach it to a radius rod with a pin at the centre. Assemble the plywood parts with glue and screws. There is a relatively simple method to realize an equatorial mount for Dobsonians, particularly if you are interested in visual use only. Whenever possible, we We will not go into any further detail on finishing the mount as Mark out and cut the aluminium angle sections. to determine your dimensions. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Our Dobsonian Mount. many dimensions, so calculating clearances from the tube outwards to Also be aware of our Sawing, these items at the appropriate time. using Rustproof The arm pivots on a piece of angled bracket, which is screwed to a raised plywood support so that the drive gear can mesh with the rack when engaged.