DIY telescope made from a magnifying glass. How to make a budget telescope with your own hands
Let's try to make a telescope. In order to make a simple but fully functional telescope yourself, you need whatman paper, black ink, stationery glue or paste and two optical lenses. We present telescope options with magnifications of thirty, fifty and one hundred times. They differ only in extended length and objective lenses.
To begin with, it is best to make a telescope with a magnification of 50 times.
From a suitable sheet of whatman paper, roll up a tube 60 - 65 cm long. The diameter should be slightly larger than the diameter of the objective lens - about 6 cm if you are using a standard spectacle lens. Unfold the sheet and ink over the part of the sheet that will become the inner surface of the telescope.
Otherwise, rays that enter the tube from a source other than the object of observation will be reflected many times and enter the eyepiece lens and veil the image.
After the inner surface is blackened, you can roll and glue the pipe. Attach an objective lens of +1 diopter (you will find it in the Optics store) to the end of the pipe as shown in the figure - using two cardboard rims with paper teeth.
The second tube with eyepiece lens 2 should move with little effort, but quite freely, in the first one.
You will most likely find the lens for the eyepiece in the photographic goods department or remove it from a binocular that is “permanently” broken. You should select a lens like this: point light at it from a distant source, such as a sunbeam, and watch where they come into focus. The distance from the lens to the focus is called the focal length of that lens (f). For our purposes, the eyepiece should have f=3-4 cm. As a rule, such lenses have a small diameter, therefore the eyepiece lens mount is somewhat different from the lens mount.
Roll a cardboard tube 6 - 7 cm long with such a diameter that the lens you selected fits tightly into it. If it is equipped with a wide metal rim, it does not fall out of the tube and does not require additional fastening at the edges.
The tube with lens 2 is secured inside the much wider tube of the telescope using two cardboard circles with holes in the middle and teeth made of less dense paper.
Next, connect the two pipes - and the telescope is ready!
The image will appear upside down; this is not important when viewing astronomical objects, but is not very convenient when observing objects on the ground. This drawback can be eliminated by using a second lens with f=3-4 cm... Insert it into the eyepiece tube, and the image will stand on its own.
A telescope with a magnification of 25 - 30 is no different from a 50x one, except for the length and lens of +2 diopters. Its length - no more than 70 cm, and even less when folded - allows you to take the telescope on hikes and store it in a backpack. To prevent the lenses from getting dirty or scratched, make a case out of cardboard, covered with adhesive tape inside and out..
Here we will briefly summarize what can be seen through a telescope with a particular aperture.
30 mm. The same, plus Jupiter's moons Europa, Io, Callisto and Ganymede. In a very fortunate coincidence - Saturn's satellite Titan. Stripes on the disk of Jupiter. Planet Neptune - in the form of a star.
40 mm. The double star Castor - Alpha Gemini separates. The Great Orion Nebula and open star clusters in the constellations Perseus, Auriga, and Canis Major and Cancer.
60 mm. The quadruple star Epsilon Lyrae is separating. The Straight Wall formation is visible in the Sea of Clouds on the Moon.
80 mm. Shadows from Jupiter's satellites are visible as they pass in front of the planet's disk. The ring nebula M57 has a dark hole at its center. Several satellites of Saturn. The Cassini gap in the rings of Saturn.
100 mm. The satellite of Rigel - Alpha Orionis - and the North Star - Alpha Ursa Minor are visible.
120 mm. Saturn's moon Enceladus. Details on the disk of Mars during oppositions are seas and polar caps made of carbon dioxide.
150 mm. Duality of Epsilon Bootes. Division of the globular cluster M13 into individual stars.
200 mm. The Encke division in the ring of Saturn is several concentric rings separated by spaces. Spirals in the Andromeda Nebula.
250 mm. Pluto. Satellites of Uranus.
300 or more. Horsehead Nebula. Satellite of Sirius. Galaxies in detail. The central star in the ring nebula M57. Globular star cluster in the M31 galaxy.
And so we summarize - in order to build a simple refracting telescope, you need only two collecting lenses - a long focal length (low optical power) for the objective and a short focal length (strong magnifying glass) for the eyepiece.
You should look for them at flea and radio markets, and at worst in eyeglass stores.
The first lens - the lens of a telescope, if you point it without anything else at some distant object, will create an inverted image of it behind itself, at a distance approximately equal to its focal length. This image can be seen on frosted glass or paper or, without any glass, by simply standing behind the lens at a distance greater than the focal length and looking in the direction of the lens.
Please note that in the latter case the eye will have to accommodate not “to infinity”, as when considering the horizon line, but as when considering a certain material object located from the eye at the same distance as the image plane. You will see a magnified inverted image of a distant object, with the magnification factor being equal to the focal length of the lens in cm divided by 25 - distance best vision human eye. If focal length If the lens is less than 25 cm, the image will be reduced. The simplest telescope is basically ready!
Now from the mechanical side. In order not to hold all this equipment in your hands, we take two tubes, one of which slides into the other, or we make them out of paper and PVA, blackening them from the inside activated carbon or a battery filled with PVA (a can of matte black paint is also suitable), and attach a lens to the end of one tube and an eyepiece to the end of the other. After this, we slide one tube into the other so that we can see a clear image removed items. The pipe is ready!!!
Essential points: lens - spectacle glass, condenser lens or achromatic gluing with a focal length of 40 - 100 cm. The diameter of the telescope entrance hole is 20 - 30 mm, if the gluing is (a lens from some kind of optical device), then more is possible. If the diameter is larger than the given values, the image may turn out to be low-contrast. To limit the diameter, we make an aperture - we cut out a cardboard circle with a diameter equal to the outer diameter of the lens, and in the center we cut out a round hole with a diameter of 20 - 30 mm. We place the aperture close to the lens in front or behind it.
The magnification of such a telescope is 20 - 50 times.
The objective and eyepiece lenses should be installed into the tube as coaxially as possible. The lens must be glass. What is visible: at 28 mm 40 times outside the city, stars up to 9th magnitude are visible, the ring of Saturn and the gap between it and the disk, satellites and two dark stripes on Jupiter (they seem more orange), the phase of Mars when it was 6 seconds in diameter , craters on the Moon, spots on the Sun (only when projected with an eyepiece, do not look with the eye!!!).
The conclusion is this: in terms of detail visibility, this product, if assembled well, will surpass 8x binoculars.
Just in case, we remind you that a +1 diopter spectacle lens has a focal length of 1 meter and it is quite sufficient for such a simple telescope. You should not follow popular recommendations and make a lens from a pair of identical lenses +0.5 diopters (concave to each other). This is a “Periscope” scheme, which has some advantages only in fields of 30-50 degrees, which is not relevant for telescopes with their fields of half a degree.
Telescope- the dream of many, because there are so many stars in the universe that you want to look at each one. Store prices for this device are a bit steep for ordinary people, so there is an option to make a telescope with your own hands.
How to make a telescope at home?
For the simplest telescope we need:
Lenses, 2 pcs.;
- thick paper, several sheets;
- glue;
- magnifying glass.
Telescope diagram.
There are two types of telescopes - refractors and reflectors. We will make a refracting telescope, since lenses for it can be bought at any pharmacy. A spectacle lens is required, diameter - 5 cm, diopters +0.5-1. For the eyepiece we will take a magnifying glass with a focal length of 2 cm.
Let's get started!
How to make the main tube for a telescope with your own hands?
From a sheet of thick paper, make a pipe with an approximate diameter of 5 cm. Then, straighten the sheet and paint the inside with black. You can use gouache paints. Rewind into a tube and secure the position using glue.
The length of our pipe should be about 2 meters.
How to make an eyepiece tube for a telescope?
We make this pipe in the same way as the main one. Length - 20 cm. Don't forget, this pipe will be put on the main one, so the diameter should be a little larger.
Once you glue the two pipes together, all that remains is to insert the lenses. Install them as shown in the diagram. Fix them well so that they are not damaged during use.
VIDEO. How to make a telescope?
A spyglass is considered to be an ancient object, the use of which allows you to easily see objects located at a long distance. But, having learned the basics of how to make a telescope yourself, you can become the owner of this wonderful optical device, to which the Age of Discovery owes a lot. By the way, made at home telescope It is suitable not only for entertaining children, but can also become a good ground observation tool. It is worth saying that homemade telescopes cope with presenting a straight, rather than inverted, image. The entire process of creating this optical instrument includes step-by-step work, as well as having at hand an arsenal of all the necessary items that you cannot do without in the work process.
So, first of all, you need to start selecting lenses. Here, glasses from magnifying glasses may well be suitable for this purpose. By the way, you can purchase them at any store specializing in optics. As for these glasses, the diopter of one of them should be from +4 to +6, and the second from -18 to -21. In terms of diameter, a positive lens should be 5 centimeters, and a negative lens should be 1-3 centimeters. Having obtained the necessary lenses, you need to take a block of wood in the form of a cylinder (it is important that its diameter fully matches the diameter of the negative lens), onto which a single layer of polyethylene film is then wound. You can secure the polyethylene with tape. If, unfortunately, polyethylene is not at hand, it is replaced with a simple bag, which everyone probably has at home.
The film is wrapped on top with a tube of paper, the layers of which must be well coated with glue. The pipe must have a length of 126 millimeters. But its outer diameter must completely correspond to the diameter of the objective lens, which is positive. Now the future creation is removed from the blank and left for some time so that it dries well. As the glue dries, the pipe will harden, and once it is completely hardened, it is wrapped in another layer of plastic film and secured with tape. But this process needs to be repeated all over again by wrapping the pipe with paper and glue. This must be done in such a way that the walls are 3-4 millimeters thick, while the length of the outer pipe should be 126 millimeters. The outer part must be removed from the inner part and left for the glue to dry completely.
Now it's time to get rid of the polyethylene. For this inner tube placed in the outer one. At this moment, the smaller element should have a larger stroke inside with a separate level of friction. If there is no friction, the outer diameter of the smaller pipe should be increased by using a couple of layers of thin paper. Now the pipes are disconnected, and the surfaces inside are coated with matte black paint. To make an eyepiece, you need to glue two identical paper rings together. A wooden block will significantly facilitate the gluing process. The rings must have an outer diameter equal to the inner diameter of the small pipe. When measured, the wall thickness will be 2 millimeters, and the elevation will be 3 millimeters. Paint of the same color is also applied to the rings, or you can use black paper to make them.
The eyepiece should be assembled following a certain sequence. From one end inner surface a small pipe is smeared with glue (you need to lubricate about 2 cm). Next, the first ring is inserted, and then a small lens, and only then the second ring is inserted. Once the eyepiece has dried, you should move on to creating the lens. To do this, make two more rings from paper with a diameter equal to the diameter of the larger lens. A circle is cut out of thin cardboard, which corresponds to the size of the lens, and a hole with a diameter of about 3 centimeters is pierced inside it. The place where the circle is glued is the end of one of the rings. Black paint is applied to the rings, after which the lens is assembled according to the principle of assembling an eyepiece. The only difference is that initially a ring with a glued circle is inserted into the pipe, which is turned inward of the pipe. The hole will become the diaphragm. At the end, put a lens with a second ring and let the pipe dry.
Probably everyone in their life has been at least a little interested in astronomy and wanted to have with them an instrument that would allow them to take a closer look at the mysteries of the starry sky.
It’s good if you have binoculars or a telescope - even with such rather weak astronomical instruments you can already admire the beauty of the starry sky. But if your interest in this science is strong enough, but there is no access to the tool at all, or the available tools do not satisfy your curiosity, you will still need a more powerful tool - telescope which you can do yourself at home. In our article step by step instructions with photos and videos on how to make a telescope with your own hands.
A factory-made telescope will cost you quite a lot, so purchasing it is only appropriate if you want to engage in amateur or amateur astronomy. professional level. But first, in order to acquire basic knowledge and skills, and finally understand whether astronomy is really for you, you should try to make a telescope with your own hands.
In many children's encyclopedias and others scientific publications you can find a description of how to make a simple telescope. Already such a tool will allow you to see craters on the Moon, the disk of Jupiter and its 4 satellites, the disk and rings of Saturn, the crescent of Venus, some large and bright star clusters and nebulae, stars, invisible to the naked eye. It is immediately worth noting that such a telescope cannot claim image quality in comparison with factory-made telescopes due to the mismatch of the purpose of the optics that will be used.
Telescope device
First, a little theory. The telescope, as in the photo, consists of two optical units - lens And eyepiece. The lens collects light from objects; its diameter directly determines the maximum magnification of the telescope and how faint objects can be observed. The eyepiece magnifies the image formed by the lens, followed by the human eye in the optical design.
There are several types of optical telescopes, two of the most common are refractor And . The reflector lens is represented by a mirror, and the refractor lens is represented by a system of lenses. At home, making a mirror for a reflector is a rather labor-intensive and precise process that not everyone can do. Unlike a reflector, inexpensive refractor lenses can be easily purchased at an optical store.
Increase telescope is equal to the ratio Fob/Fok (Fob is the focal length of the lens, Fok is the eyepiece). Our telescope will have a maximum magnification of about 50x.
To make a lens, you need to purchase a spectacle lens blank with a power of 1 diopter, which corresponds to a focal length of 1 m. Such blanks usually have a diameter of about 70 mm. Unfortunately, spectacle lenses manufactured in the form of menisci, are poorly suited for this application, but you can stop at them. If you have a long focal length biconvex lens, it is recommended to use this one.
An ordinary magnifying glass (loupe) with a small diameter of about 30 mm can serve as an eyepiece. A good option there may also be an eyepiece from a microscope.
As housing you can use two tubes made of thick paper, one short - about 20 cm (eyepiece unit), the second about 1 m (the main part of the tube). The short pipe is inserted into the long one. The body can be made either from a wide sheet of whatman paper, or from a roll of wallpaper, rolled into a tube in several layers and glued with PVA glue. The number of layers is selected manually until the pipe becomes sufficiently rigid. The inner diameter of the main pipe should be equal to the diameter of the spectacle lens.
The lens (spectacle lens) is mounted in the first tube with the convex side outward using a frame - rings with a diameter equal to the diameter of the lens and a thickness of about 10 mm. A disk is installed immediately behind the lens - diaphragm with a hole in the center with a diameter of 25 - 30 mm - this is necessary in order to reduce significant image distortions resulting from a single lens. This will reduce the amount of light collected by the lens. The lens is installed closer to the edge of the main tube.
The eyepiece is installed in the eyepiece assembly closer to its edge. To do this, you will have to make an eyepiece mount from cardboard. It will consist of a cylinder equal in diameter to the eyepiece. This cylinder will be attached to inside pipes with two disks with a diameter equal to the internal diameter of the eyepiece assembly with a hole equal in diameter to the eyepiece.
Focusing will be accomplished by changing the distance between the lens and the eyepiece, due to the movement of the eyepiece assembly in the main tube, and fixation will occur due to friction. It is convenient to focus on bright and large objects such as the Moon, bright stars, nearby buildings.
When building a telescope, it is necessary to take into account that the lens and eyepiece must be parallel to each other, and their centers must be strictly on the same line.
You can also experiment with the diameter of the aperture opening and find the optimal one. If you use a lens with an optical power of 0.6 diopters (the focal length is 1/0.6, which is about 1.7 m), this will increase the aperture opening and increase the magnification, but will increase the length of the tube to 1.7 m.
It is always worth remembering that you should not look at the sun through a telescope or any other optical device. This will instantly damage your vision.
So, you have become familiar with the principle of building a simple telescope and can now make it yourself. There are other telescope options made from spectacle lenses or telephoto lenses. You can find any manufacturing details, as well as other information you are interested in, on websites and forums on astronomy and telescope construction. This is a very broad field, and is practiced by both complete beginners and professional astronomers.
And remember, you just have to plunge into the previously unknown world of astronomy - and if you wish, it will show you many treasures of the starry sky, teach you the techniques of observation, photographing completely different objects and much more that you didn’t even know about.
Clear skies to you!
Video: how to make a telescope with your own hands
Eyeglass lenses are a good material for a quality telescope. Before you buy a good telescope, you can make one yourself from inexpensive and available funds. If you or your child want to get interested in astronomical observations, then the construction homemade telescope will help you study both the theory of optical devices and observational practice.
Despite the fact that a refracting telescope built from spectacle glasses will not show you much in the sky, the experience and knowledge gained will be priceless. Afterwards, if you are interested in telescope construction, you can build a more advanced reflecting telescope, for example Newton’s system (see other sections of our website).
There are three types of optical telescopes: refractors (a lens system as a lens), reflectors (a lens - a mirror), and catadioptric (mirror-lens). All the most modern large telescopes- reflectors, their advantage is the absence of chromatism and possible large sizes lens, because the larger the diameter of the lens (its aperture), the higher its resolution, and the more light is collected, and therefore the fainter astronomical objects are visible through the telescope, the higher their contrast, and the greater magnifications can be applied.
Refractors are used where high precision and contrast are required or in small telescopes. And now about the simplest refractor, with a magnification of up to 50 times, with which you can see: the largest craters and mountains of the Moon, Saturn with its rings (like a ball with a ring, not a “dumpling”!), bright satellites and the disk of Jupiter, some stars invisible to the naked eye.
Any telescope consists of a lens and an eyepiece; the lens builds a magnified image of the object that is viewed, then through the eyepiece. The distance between the lens and the eyepiece is equal to the sum of their focal lengths (F), and the magnification of the telescope is equal to Fob./Fok. In my case it is approximately 1000/23 = 43 times, i.e. 1.72D with an aperture of 25 mm.
1 - eyepiece; 2 - main pipe; 3 - focusing tube; 4 - diaphragm; 5 - tape that attaches the lens to the third tube, which can be easily removed, for example, to replace the diaphragm; 6 - lens.
As a lens, let's take a blank lens for glasses (can be bought at any "Optics") with a power of 1 diopter, which corresponds to a focal length of 1 m. Eyepiece - I used the same achromatic coated gluing as for the microscope, I think for such a simple device - this is a good option. As a body, I used three tubes made of thick paper, the first about a meter, the second ~20 cm. The short one is inserted into the long one.
The lens - the lens is attached to the third tube with the convex side facing outwards, a disk is installed immediately behind it - a diaphragm with a hole in the center with a diameter of 25-30 mm - this is necessary, because a single lens, and even a meniscus, is a very bad lens and for obtaining of tolerable quality, you have to sacrifice its diameter. The eyepiece is in the first tube. Focusing is done by changing the distance between the lens and the eyepiece, moving or extending the second tube, it is convenient to focus on the Moon. The lens and eyepiece must be parallel to each other and their centers must be strictly on the same line; the diameter of the tube can be taken, for example, 10 mm larger than the diameter of the aperture hole. In general, when making a case, everyone is free to do as they wish.
A few notes:
- do not install another lens after the first one in the lens, as advised on some sites - this will only cause light loss and deterioration in quality;
- also do not install the diaphragm deep in the pipe - this is not necessary;
- it’s worth experimenting with the diameter of the diaphragm opening and choosing the optimal one;
- you can also take a lens of 0.5 diopters (focal length 2 m) - this will increase the aperture opening and increase the magnification, but the length of the tube will become 2 meters, which may be inconvenient.
A single lens is suitable for the lens, the focal length of which is F = 0.5-1 m (1-2 diopters). It's not difficult to get; it is sold in an optical store that sells glasses lenses. Such a lens has a whole bunch of aberrations: chromaticism, spherical aberration. Their influence can be reduced by using lens aperture, that is, reducing the entrance aperture to 20 mm. What's the easiest way to do this? Cut a ring out of cardboard equal to the diameter of the pipe and cut the same entrance hole (20 mm) inside, and then place it in front of the lens almost close to the lens.
It is even possible to assemble a lens from two lenses in which the chromatic aberration that appears as a result of light dispersion will be partially corrected. To eliminate it, take 2 lenses different shapes and material - collecting and scattering - with different dispersion coefficients. A simple option: buy 2 spectacle lenses made of polycarbonate and glass. In a glass lens the dispersion coefficient will be 58-59, and in polycarbonate it will be 32-42. the ratio is approximately 2:3, then we take the focal lengths of the lenses with the same ratio, say +3 and -2 diopters. We add these values and get a lens with a focal length of +1 diopter. We fold the lenses tightly; the collective should be the first to the lens. If it is a single lens, then it should have the convex side facing the object.
How to make a telescope without an eyepiece?! The eyepiece is the second important detail telescope, we can’t go anywhere without it. It is made from a magnifying glass with a focal distance of 4 cm. Although for the eyepiece it is better to use 2 plano-convex lenses (Ramsden eyepiece), setting them at a distance of 0.7f. The ideal option is to get the eyepiece from ready-made instruments (microscope, binoculars). How to determine the magnification size of a telescope? Divide the focal length of the lens (for example, F=100cm) by the focal length of the eyepiece (for example, f=5cm), you get 20 times the magnification of the telescope.
Then we need 2 tubes. Insert the lens into one, and the eyepiece into the other; Then we insert the first tube into the second. Which tubes should I use? You can make them yourself. Take a sheet of whatman paper or wallpaper, but be sure to have a thick sheet. Roll the tube to fit the diameter of the lens. Then you fold another sheet of thick paper and place the eyepiece (!) tightly into it. Then insert these tubes tightly into one another. If a gap appears, wrap the inner tube in several layers of paper until the gap disappears.
Now your telescope is ready. How to make a telescope for astronomical observations? You're just blackening out internal cavity each pipe. Since we are making a telescope for the first time, we will use a simple method of blackening. Just paint the inside of the pipes with black paint.
Often the geometric center of the lens does not coincide with the optical one, so if you have the opportunity to have the lens sharpened by a specialist, do not neglect it. But in any case, an unground spectacle lens blank will do. Lens diameter of great importance does not exist for our telescope. Because spectacle lenses are highly susceptible to various aberrations, especially the edges of the lens, then we will aperture the lens with a diaphragm of about 30 mm in diameter. But to observe different objects in the sky, the aperture diameter is selected empirically and can vary from 10 mm to 30 mm.
For an eyepiece, of course, it is better to use an eyepiece from a microscope, level or binoculars. But in this example I used a lens from a point-and-shoot camera. The focal length of my eyepiece is 2.5 cm. In general, any positive lens of small diameter (10-30mm) with a short focus (20-50mm) is suitable as an eyepiece.
Determining the focal length of the eyepiece yourself is easy. To do this, point the eyepiece at the Sun and place a flat screen behind it. We will zoom in and out of the screen until we get the smallest and brightest image of the Sun. The distance between the center of the eyepiece and the image is the focal length of the eyepiece.