A spyglass is an antique item that allows you to observe distant objects. However, this optical device, which was used in the era of the great geographical discoveries, has not lost its popularity to this day. A spyglass can be made with your own hands, and not only for games or historical reconstruction. This terrestrial observation instrument should provide an upright image, not an upside-down image.
Necessary
- - 2 lenses;
- - thick paper (Whatman paper or other);
- - epoxy resin or nitrocellulose glue;
- - black matte paint (for example, auto enamel);
- - wooden blank;
- - polyethylene;
- - Scotch;
- - scissors, ruler, pencils, brushes.
Instructions
Step 1
Pick up your lenses. Spectacle lenses, which can be purchased at an optical store, are suitable. One of them should be from +4 to +6 diopters, the other from -18 to -21. The diameter of the positive lens is 4-5 cm, and the diameter of the negative lens is 1-3 cm.
Step 2
On a wooden cylindrical blank, the diameter of which is equal to the diameter of the negative lens, wrap 1 layer of plastic film and secure it with tape. You can take a regular shopping bag. Wrap a paper tube over the film, carefully coating each layer with glue. The pipe length should be 126 mm. Its outer diameter is equal to the diameter of the objective lens (positive). Remove the pipe from the blank and let dry.
Step 3
When the glue is dry and the pipe hardens, wrap it with one layer of plastic wrap and tape it together. In the same way as in the previous step, wrap the pipe with paper and glue so that the wall thickness is 3-4 mm. The length of the outer tube is also 126 mm. Remove the outer part from the inner part and let dry.
Step 4
Remove the polyethylene. Insert the inner tube into the outer one. The smaller part should move more inside with some friction. If there is no friction, increase the outer diameter of the smaller pipe using one or more layers of tissue paper. Disconnect the pipes. Paint the interior surfaces with matt black paint. Dry the parts.
Step 5
To make an eyepiece, glue 2 identical paper rings together. This can be done on the same wooden blank. The outer diameter of the rings is equal to the inner diameter of the small pipe. The wall thickness is about 2 mm and the height is about 3 mm. Paint the rings black. They can be made immediately from black paper.
Step 6
Assemble the eyepiece in the following sequence. Grease the inner surface of the small pipe at one end with glue for two centimeters. Insert the first ring, then the small lens. Place the second ring. Avoid getting glue on the lens.
Step 7
While the eyepiece is drying, make a lens. Make 2 more paper rings. Their outer diameter should be equal to the diameter of the large lens. Take a sheet of thin cardboard. Cut a circle out of it with a diameter equal to the diameter of the lens. Make a round hole with a diameter of 2.5-3 cm inside the circle. Glue the circle to the end of one of the rings. Also paint these rings with black paint. Assemble the lens in the same way as you assembled the eyepiece. The only difference is that first, a ring is inserted into the pipe with a circle glued to it, which must face the inside of the pipe. The hole acts as a diaphragm. Put on the lens and the second ring. Let the structure dry
Step 8
Insert the eyepiece knee into the objective knee. Select a distant object. Aim the tube in focus by sliding and expanding the tubes.
