Everyone probably wanted to assemble their own telescope in childhood from scrap materials, but somehow they never got around to it... How to make a telescope yourself? Yes, it’s very simple, because now there are many schemes amateur telescopes a wide variety of designs.
First, we need an ordinary sheet of Whatman paper. The first step is to paint one side of the sheet black - it will be the inside. Painting is needed so that it is dark inside the telescope tube, which will be the rolled up Whatman paper, otherwise you will see a rather cloudy image in the eyepiece and are unlikely to find the answer to the question “how to make a telescope.” Yes, by the way, a sheet of Whatman paper should be about 1 meter in length - this is exactly what is ideal for a homemade telescope.
So, the tube of the future telescope is ready. Now you need to find a lens for the lens. For a device with a focal length of a meter, glass with a diopter of +1 is suitable. What’s good is that similar lenses are sold in any optical store, so you can even buy glasses in reserve.
Next in the action plan called “How to make a telescope” is the next item - attaching the lens. The lens is attached to one end of your telescope using cardboard rings and tape. There is an option to secure the glass with electrical tape, but this is not always suitable. Once you have firmly connected the lens, you can move on to the next step.
To completely forget about the cloudiness of the image, you also need to make a diaphragm. This is the name of a small cardboard circle with a hole in the middle. It is possible to set the aperture both behind the lens and in front of it - this will not affect the final result.
In any case, experiments are welcome, so perhaps your reflector model can become an illustration for the book “How to Make a Telescope.”
If you are not an experimenter at all, then you can look for tables of correspondence between the sizes of objective lenses and the diameters of holes in the apertures.
For example, for a 70mm lens, an aperture with a 40mm aperture is sufficient.
In specialized stores, small glasses of eyepieces are quite expensive - up to 1.5 thousand rubles apiece. But we are not interested in the question “how to make a telescope at an expensive price”; on the contrary, we want to save money. That's why you can forget about going to stores.
Even the glass from the binoculars you played with as a child will be suitable for the eyepiece. It is important that it is glass and not a piece of plastic, because plastic makes the image cloudy.
The eyepiece is attached to the end of the second, small tube, using the same cardboard rings and tape. You can also use plastic caps and lids from chip cans. Why do we connect a small pipe to a large one in such a way that we do not get a static structure - after all, we may need focusing. That is why it is necessary to make the diameter of the small pipe slightly smaller than the diameter of the large one.
Making a tripod is optional - you can even use a stack of books under the tripod, since homemade telescope It does not necessarily have to be fixed statically, because the magnification it provides is quite small, which means that the picture will not shake.
So you have learned how to make a reflecting telescope at home with a minimum of cost!
Make a telescope with your own hands? Nothing could be easier!
Many people, looking up at the starry sky, admire the alluring mystery of outer space. I want to look into the endless expanses of the universe. See craters on the moon. Rings of Saturn. Many nebulae and constellations. So today I will tell you how to make a telescope at home.
First, you need to decide how much magnification is required. The fact is that the larger this value, the longer the telescope itself will be. At 50x magnification the length will be 1 meter, and at 100x magnification it will be 2 meters. That is, the length of the telescope will be directly proportional to the magnification.
Let's say it will be a 50x telescope. Next, you need to purchase two lenses at any optics store (or on the market). One for the eyepiece (+2)-(+5) diopters. The second is for the lens (+1) diopter (for a 100x telescope, (+0.5) diopter is required).
Then, taking into account the diameters of the lenses, it is necessary to make a pipe, or rather two pipes - one should fit tightly into the other. Moreover, the length of the resulting structure (in the extended state) should be equal to the focal length of the lens. In our case, 1 meter (for a lens (+1) diopter).
How to make pipes? To do this, you need to wrap several layers of paper on a frame of the appropriate diameter, coating them with epoxy resin (you can use other glue, but the last layers are better strengthened with epoxy). You can use the remnants of wallpaper that are lying around idle after renovating your apartment. You can experiment with fiberglass, then it will be a more serious design.
Next, we build the objective lens (+1) diopter into the outer tube, and (+3) diopter into the inner eyepiece. How to do this? Your imagination is the main thing to ensure precise parallelism and alignment of the lenses. In this case, it is necessary to ensure that the distance between the lenses when moving the pipes apart is within the focal length of the objective lens, in our case it is 1 meter. In the future, by changing this parameter, we will adjust the sharpness of our image.
For convenient use of the telescope, a tripod is needed to clearly fix it. At high magnification, the slightest trembling of the tube leads to blurring of the image.
If you have any lenses, you can find out their focal length in the following way: focus sunlight onto a flat surface until you get the smallest point possible. The distance between the lens and the surface is the focal length.
So, to achieve a telescope magnification of 50 times, you need to place a lens of (+1) diopter at a distance of 1 meter from the lens of (+3) diopter.
For 100x magnification, we use lenses (+0.5) and (+3) changing the distance between them by 2 meters.
And this video shows the process of creating a similar telescope:
Enjoy your astronomical viewing!
Sometimes you find all sorts of rubbish in your bins. In dresser drawers in the country, in chests in the attic, among things under an old sofa. Here are grandma's glasses, here is a folding magnifying glass, here is a spoiled eye"" from front door, and here are a bunch of lenses from disassembled cameras and overhead projectors. It’s a shame to throw it away, and all this optics sits idle, just taking up space.
If you have the desire and time, then try to make a useful thing out of this trash, for example, a spyglass. Do you want to say that you’ve already tried it, but the formulas in the help books turned out to be painfully complicated? Let's try again, using simplified technology. And everything will work out for you.
Instead of guessing by eye what will happen, we will try to do everything further according to science. Lenses are magnifying and minimizing. Let's divide all the available lenses into two piles. In one group there are magnifying ones, in the other group there are diminutive ones. The disassembled peephole from the door has both magnifying and minimizing lenses. Such small lenses. They will be useful to us too.
Now we will test all magnifying lenses. To do this, you need a long ruler and, of course, a piece of paper for notes. It would be nice if the sun was still shining outside the window. With the sun, the results would be more accurate, but a burning light bulb will do. We test lenses as follows:
-Measure the focal length of the magnifying lens. We place the lens between the sun and the piece of paper, and moving the piece of paper away from the lens or the lens away from the piece of paper, we find the smallest point of convergence of the rays. This will be the focus length. We measure it (focus) on all lenses in millimeters and write down the results, so that later we don’t have to worry about determining the suitability of the lens.
So that everything continues to be scientific, we remember a simple formula. If 1000 millimeters (one meter) is divided by the focal length of the lens in millimeters, we get the lens power in diopters. And if we know the diopters of the lenses (from an optics store), then dividing the meter by diopters we get the focal length. Diopters on lenses and magnifying glasses are indicated by a multiplication symbol immediately after the number. 7x; 5x; 2.5x; etc.
Such testing will not work with miniature lenses. But they are also designated in diopters and also have a focus according to diopters. But the focus will already be negative, but not at all imaginary, quite real, and we will now be convinced of this.
Let's take the longest focal length magnifying lens in our kit and combine it with the strongest reducing lens. The total focal length of both lenses will immediately decrease. Now let's try to look through both lenses assembled, diminutive to ourselves.
Now we slowly move the magnifying lens away from the diminutive lens, and in the end we may get a slightly enlarged image of the objects outside the window.
The mandatory condition here must be the following. The focus of the diminutive (or negative) lens must be smaller than the magnifying (or positive) lens.
Let's introduce new concepts. The positive lens, also known as the front lens, is also called the objective lens, and the negative or rear lens, the one closer to the eye, is called the eyepiece. The power of the telescope is equal to the focal length of the lens divided by the focal length of the eyepiece. If the division results in a number greater than one, then the telescope will show something; if it is less than one, then you will not see anything through the telescope.
Instead of a negative lens, short-focus positive lenses can be used in eyepieces, but the image will be inverted and the telescope will be slightly longer.
By the way, the length of the telescope is equal to the sum of the focal lengths of the lens and eyepiece. If the eyepiece is a positive lens, then the focus of the eyepiece is added to the focus of the lens. If the eyepiece is made of a negative lens, then plus to minus is equal to minus and from the focus of the lens, the focus of the eyepiece is already subtracted.
This means the basic concepts and formulas are as follows:
-Lens focal length and diopter.
-Magnification of the telescope (the focus of the lens is divided by the focus of the eyepiece).
-The length of the telescope (the sum of the focal points of the lens and eyepiece).
THAT'S THE COMPLEXITY!!!
Now a little more technology. Remember, probably, that telescopes are made folding, from two, three or more parts - elbows. These knees are made not only for convenience, but also for specific adjustment of the distance from the lens to the eyepiece. Therefore, the maximum length of the telescope is slightly greater than the sum of the foci, and the moving parts of the telescope allow you to adjust the distance between the lenses. Plus and minus to the theoretical pipe length.
The lens and eyepiece must be on the same (optical) axis. Therefore, there should be no looseness of the pipe elbows relative to each other.
The inner surface of the tubes must be painted matte (not shiny) black, or the inner surface of the tube can be covered with black (painted) paper.
It is advisable that internal cavity The spyglass was sealed, then the pipe would not sweat inside.
And the last two tips:
-don’t get carried away with large magnifications.
-if you want to make a homemade telescope, then my explanations will probably not be enough for you, read special literature.
If you don’t understand what’s what in one book, take another, third, fourth, and in some book you will still get the answer to your question. If it happens that you don’t find the answer in books (or on the Internet), then Congratulations! You have reached a level where the answer is already expected from YOU.
I found a very interesting article on the Internet on the same topic:
http://herman12.narod.ru/Index.html
A good addition to my article is offered by the author from prozy.ru Kotovsky:
So that even such a small amount of work does not go to waste, we should not forget about the diameter of the lens, on which the exit pupil of the device depends, calculated as the diameter of the lens divided by the magnification of the tube.
For a telescope, the exit pupil can be about a millimeter. This means that from a lens with a diameter of 50 mm you can squeeze (by choosing a suitable eyepiece) 50x magnification. At higher magnification, the image will deteriorate due to diffraction and lose brightness.
For a “terrestrial” tube, the exit pupil must be at least 2.5 mm (better - larger. For military binoculars BI-8 - 4 mm). Those. for “terrestrial” use, you should not squeeze more than 15-20x magnification from a 50 mm lens. Otherwise, the picture will darken and blur.
It follows from this that lenses with a diameter of less than 20 mm are not suitable for the lens. Perhaps 2-3x magnification is enough for you.
In general, a lens from spectacle lenses- non-comme il faut: meniscus distortions due to convex-concave. There must be a duplex lens, or even a triplex if it is short-focus. You can't just find a good lens among the trash. Perhaps there’s a “photo gun” lens lying around (super!), a ship’s collimator or an artillery rangefinder :)
About eyepieces. For a Galilean tube (an eyepiece with a diverging lens), you should use a diaphragm (a circle with a hole) with a diameter equal to the calculated size of the exit pupil. Otherwise, when the pupil moves away from the optical axis, there will be severe distortion. For a Kepler tube (converging eyepiece, the image is inverted), single-lens eyepieces produce large distortions. You need at least a two-lens Huygens or Ramsden eyepiece. Better prepared - from a microscope. As a last resort, you can use a camera lens (don't forget to fully open the blade aperture!)
About the quality of lenses. Everything from the door peepholes goes into the trash! From the remaining ones, select lenses with anti-reflective coating (characteristic purple reflection). The absence of clearing is allowed on surfaces facing outward (toward the eye and the object of observation). The best lenses- from optical instruments: film cameras, microscopes, binoculars, photo enlargers, overhead projectors - at worst. Don’t rush to disassemble finished eyepieces and objectives made from several lenses! It is better to use it entirely - everything is selected in the best possible way.
And one more thing. At high magnifications (>20) it is difficult to do without a tripod. The picture is dancing - you can’t make out anything.
You should not try to make the pipe shorter. The longer the focal length of the lens (more precisely, its ratio to the diameter), the lower the demands on the quality of all optics. This is why in the old days telescopes were much longer than modern binoculars.
I made the best homemade trumpet this way: a long time ago in Salavat I bought a cheap children's toy - a plastic spyglass (Galileo). She had 5x magnification. But she had a duplex lens with a diameter of almost 50 mm! (Apparently, substandard from the defense industry).
Much later, I purchased an inexpensive Chinese 8x monocular with a 21mm lens. There is a powerful eyepiece and a compact wrapping system on prisms with a “roof”.
I "crossed" them! I removed the eyepiece from the toy and the lens from the monocular. Folded, stapled. The inside of the toy was previously covered with black velvet paper. Got a powerful 20x compact pipe of high quality.
A factory-made telescope is quite expensive, so it is advisable to buy it if you are seriously interested in astronomy. And amateurs can try to assemble a telescope with their own hands.
As you know, there are two types of telescopes:
- Reflex. In these devices, the role of light-collecting elements is performed by mirrors.
- Refractory– equipped with an optical lens system.
DIY refracting telescope
The design of a refracting telescope is quite simple. At one end of the device there is a lens - a lens that collects and focuses light rays. At the other end there is an eyepiece - a lens that allows you to view the image that comes from the lens. The lens is placed in a main tube called the tube, and the eyepiece is placed in a smaller tube called the eyepiece assembly.
An ordinary telescope made from a magnifying glass
- Making the main pipe. Take a sheet of thick paper and roll it into a tube using a flat stick or a suitable pipe with a diameter of 5 cm. The paper inside should be painted black and not shiny. We make the pipe 1.9 meters long.
- Making an eyepiece tube. It should be put on the end of the main one. We roll it up from a sheet of paper 25 cm long and glue it. The inner diameter of the eyepiece tube must match the outer diameter of the main tube so that it moves effortlessly along it.
- Working with lenses. We make two lids from thick paper. We will place the first one where the lens will be, and we will attach the second one to the end of the eyepiece tube. In the middle of each cap we will make a hole with a diameter slightly smaller than the diameter of the lenses. We install the lenses with their convex side outward.
To take interesting photographs of the starry sky, you can attach a webcam to a telescope.
Telescope from binoculars
From ordinary eight-power binoculars you can build a telescope that provides magnification of over 100 times. Pipes can be glued together from whatman paper. Lenses are suitable from old filmoscopes or similar in magnification. We use the calculation of a simple telescope, and select the length of the device and the distance between the eyepiece lenses experimentally.
There is no need to disassemble the binoculars - the tubes are put directly on it. For ease of use, you can make a tripod. Such a telescope from binoculars allows you to see mountains and craters on the surface of the Moon, satellites of Jupiter, etc.
Conclusions
Making a homemade telescope at home is not particularly difficult. Even a high school student can do this kind of work. For a child, a device with a magnification of 30–100 times will be sufficient.
However, there are home craftsmen who can independently assemble a three-hundred-power high-quality telescope. Such skills come with experience and can be useful to those who are seriously interested in astronomy.
