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The "Deep Space Scope" Design

Home | Astronomy | DS-3 | Finish the mirror box

We now need to finish the mirror box. This consists of creating breathing holes in the bottom plate and drilling holes to receive the trusses.

• Using a jig saw, cut four holes in the mirror box back for cooling. Three of these holes need to be 3 1/2" in diameter, at 120 degree intervals, at 5" radius from the center. We also want a 3 1/2" hole cut at the center of the back plate.  See the picture of the back plate under mirror box construction above. Notice that these cooling holes are located 180 degrees through the center from the mirror cell columnating screws.
  
• We now need to drill 6 holes in the top that will hold the truss tubes. See the picture of the mirror box under mirror box construction above. The trusses are firmly attached to the mirror box by friction, caused by bending the trusses as they attach to the secondary cage. These holes will go completely through the 1" top of the mirror box. Drill pilot holes, 5/8" from the edge of the main mirror hole. Make these holes 1" off of the center of three points, 120 degrees apart. Notice that one of the three sets is directly at the back of the mirror box.  Then, cut these holes to be 3/4" in size with a normal drill bit or a forsner bit.
• Cut small pieces of wood, maybe 1 1/2" in diameter. Glue these pieces over the truss holes, from the inside. This now defines how far the trusses can go into the truss holes.
• We now want to place the screws that will be used to hold the mirror cover. See the picture of the mirror box under mirror box construction above. Drill holes for three screws, 120" apart, 3/8" from the edge of the primary mirror hole. Notice that these holes are centered between the LARGER spaces between trusses. Screw the screws into these holes. Cut holes into the mirror cover, that will allow the screw heads to pass over. Then, cut or sand the mirror cover so that it can rotate slightly, binding against the screws. You will notice that I am doing this in the picture.