The course of self-made high-power astronomical telescope

The tutorial of self-made high-powered astronomical telescope is as follows:

Equipment yellow cardboard, convex lens

manufacture

1, choose a convex lens with a focal length of 30 ~ 50 mm as the eyepiece, which can be replaced by a magnifying glass for repairing clocks and watches. The objective lens is a convex lens with a focal length of about 1 m, which can be replaced by an old optical lens with a focal length of 100 degrees.

2. The length of the lens barrel can only be determined by measuring the focal length of the convex lens. Put the objective lens and eyepiece in the sun, put a blank sheet of paper on the other side of the lens, adjust the distance between the paper and the lens so that the sun image is clearly on the blank sheet, and measure the distance between the lens and the paper with a ruler, which is the focal length of the lens.

3. The lens barrel is made of yellow cardboard. The whole lens barrel is divided into two parts: the objective lens barrel and the eyepiece lens barrel. The diameter of the objective lens barrel is approximately equal to the diameter of the objective lens and the length is approximately equal to the focal length of the objective lens. The outer diameter of the eyepiece lens barrel is slightly smaller than the inner diameter of the objective lens barrel, so that the eyepiece lens barrel can be inserted into the objective lens barrel and the focal length can be adjusted back and forth. The inner diameter of the eyepiece lens barrel is about equal to the diameter of the eyepiece lens, and its length is longer than the focal length of the eyepiece100 mm.

The lens barrel is made of yellow cardboard cut into strips with a width of 70 ~ 80mm. Find a circular tube with a diameter equal to the diameter of the lens as the core. Wrap the yellow paper tape around the core round and round, without overlapping or gaps. The two ends of the paper tape and the joint can be connected by kraft paper coated with glue. After the first layer is rolled, glue is coated on the outside of the yellow cardboard, and then the second layer is wound in the opposite direction to the first layer.

After winding, apply glue, and then wind the third layer. The winding direction is opposite to that of the second layer. Generally, winding the third layer is enough. Stick a layer of kraft paper on the outermost layer, remove the core and dry it vertically indoors. After drying, black the inner layer of the lens barrel with black ink to eliminate the influence of stray light.

4. Install the lens in the lens barrel so that the main optical axes of the objective lens and eyepiece are on the center line of the lens barrel. The installation of the lens depends on the size of the lens. If the lens diameter is smaller than the inner diameter of the lens barrel, it can be installed as shown in figure 19-4a, and if the lens diameter is equal to the inner diameter of the lens barrel, it can be installed as shown in figure b. ..

After the lens is installed, you can insert the eyepiece lens barrel into the objective lens barrel, aim at the high beam and observe with your eyes, and adjust the front and rear positions of the eyepiece and the objective lens so that the high beam falls in the center of the field of view seen by the telescope, which means that the main optical axis of the eyepiece falls on the center line of the lens barrel, otherwise the position of the eyepiece needs to be adjusted appropriately until it meets the requirements.

(5) Install a bracket on the lens barrel. The bracket can be a movable tripod or other forms, but the lens barrel must be stable when it rotates. The bracket should be installed at the center of gravity of the telescope tube. There should be enough friction at the joints to keep the telescope stable at any position.