building a dobsonian telescope - tube box

VIDEO QUICKLINKS


"Making the Spider Video"
Time (1:54)


"Tailgate"
Time (1:57)

"Focal Length of Mirror "
Time (1:30)

"Mounting Blocks"
Time (1:35)

There are three parts to the finished telescope:

• Telescope Tube
  - Making the spider
  - Eyepiece Holder
  - Making the Tailgate
• Rocker Box/Ground Board
• Tube Box
• Inserting Mounting Blocks
• Finding Focal Length of Mirror
• Positioning Eyepiece and Spider
• Using the Telescope

The Tube Box and Rocker Box will need to be complete before you go to school.   You will also need to prefabricate part of the Telescope Tube as well.

Tube Box Construction

The Tube box will hold the telescope tube. Because sonotubes vary in size, you will need to select your sonotube before building this part. This will help ensure that the sonotube will fit into the box once you're done. You will need the following parts for the Tube Box:

• 2 Part B boards (8.5" x 12")
• 2 Part A boards (8.5" x 8.5")
• 2 Part G boards (6" diameter circular cut)
• 4-6 screws (for securing G to B)
• 8 nails
• wood glue
• drill with cutting and driver bits
• hammer

1. Find the center point on the 2 Part B boards. To do this draw a diagonal line from the top left corner to the bottom right and repeat from Top right to bottom left.

2. Turn B over and place a bead of wood glue down each of the short sides (i.e., the 8.5" sides).

3. Position 2 Part As on the wood glue and nail to Part B forming a table like object (i.e., three sides of a box). You may want to double check to be sure your tube fits at this stage. If the tube is too large or small for the box, you may have to make adjustments (add scrap to expand or cut pieces down to fit).

4. Turn the second part B over. Put a bead of wood glue along the short sides (8.5" long).

5. Position B over the open end of the table-like object forming a box. Nail B to A.

6. Find the center point on G and drill a pilot hole with a large bit. The safest way to do this is to place a piece of scrap plywood under piece G and drill into the scrap slightly. Line up the center of G with the Center of B. Drill pilot holes in G and screw the G to B.

7. Repeat with the other side B.

8. The finished Tube Box should look like this.

9. Slide the telescope tube into the tube box. If the box is loose, use thin pieces of wood or masonite to secure. After your tube is complete, you will want to balance it in the tube box. (See finishing instructions)

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