Hobbies And Interests
Things You'll Need
Instructions
Making the Wood Mirror Base
Cut the 5/4 wood to a circle that has the same diameter as the inner diameter of the telescope tube using the jig saw. For our example, we'll use an 8 inch inner diameter tube.
Draw an equilateral triangle on the wood circle. Each side of the triangle will be approximately 7 1/8 inches long. Draw three more lines, each parallel to the triangle's three sides, and each 1 inch closer to the edge of the circle. In effect, you will be drawing a larger triangle, whose sides meet beyond the edge of the 8 inch wood circle. We will refer to these as the inner and outer lines.
Cut the circle along the outer lines. Discard the three small arcs that were removed. Sand the outer edge of the base to remove any splinters. Sand the curved arcs until they are smooth and remove any jig saw blade chatter.
Test-fit the base into the telescope tube. The base should fit securely into the tube at the base and be able to slide in and out without wobbling or dropping out of the tube when inserted.
Mark the three arcs --- the points at which the wood base "legs" contact the telescope tube. Mark the center point of the arcs and drill a 1/8 inch hole though the telescope tube at the center point of the arc, 1/2 inch from the bottom edge of the tube.
Making the Floating Mirror Cell
Cut a circle from the 3/8 inch hardboard that is identical in size to the telescope mirror's outer diameter. For an 8 inch telescope, the mirror should be just slightly smaller than the tube. We will assume a 7 1/2 inch diameter mirror. Sand any irregularities out of the hardboard circle. This part must match the mirror's circumference exactly.
Lay the wood base on top of the hardboard circle. Draw the outline of the wood base onto the hardboard. Locate the center point of each of the three "legs" on the hardboard. Draw a line from the centerpiece of the leg to the point that would be the exact center of the triangle. Each line will run down the center of the leg to meet the other three at a common point at the triangle's center. On this line, drill a 1/4 inch hole that is 1 1/2 inches from the edge of the circle.
Cut the 5/16 threaded rod into three equal pieces. Thread each piece into the three holes just drilled into the hardboard circle. The 1/4 inch holes are smaller than the threaded rod and will allow the rod to bite into the hardboard. Add a drop of superglue to the final threads on the rod just as it screws into the hardboard. This will keep the rods in place. File the top side of the rods smooth with the surface of the hardboard disk. When complete, the disk will look like a three-legged stool standing on threaded rod legs.
Apply 13 to 15 nickel-sized globs of silicone glue to the top side of the hardboard circle, which is the side opposite the threaded rod. Space the globs equally across the surface of the disk. It may be helpful to draw a grid to ensure the globs are evenly spaced.
Set the mirror lightly onto the adhesive globs. Center the mirror on the hardboard so that the outer perimeters are aligned. Allow it to dry before moving.
Connecting the Base to the Floating Mirror Cell
Set the mirror support on the wood base, so that the threaded rod legs rest on the base. Mark the points where the legs touch the base.
Drill a 3/8 inch hole for the threaded rod to pass through the wood base. Slide one of the 2-inch-long springs onto each leg and insert the legs through the wood base.
Fasten the threaded rod legs with a washer and wing nut on the bottom side of the wood base. As a result, the mirror cell is supported by the springs, yet can be tilted in order to align it with the optics in the telescope.
Slide the mirror cell into the telescope. Fasten the wood base to the telescope through the holes drilled in the telescope tube in Step 1 using the 1 1/4 inch pan head wood screws.