DIY Galilean telescope. How to make a reliable and powerful telescope yourself at home. Detailed diagrams for assembling the structure - a do-it-yourself refracting telescope from scrap materials. An ordinary telescope made from a magnifying glass
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 ink 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 inner surface 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. The lens should be selected as follows: direct light at it from a distant source, for example 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 (with a small optical power) - for the lens and a short-focus (strong magnifier) 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 the focal length of the lens is less than 25 cm, the image will be reduced. The simplest telescope, 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 of the distant objects. 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 - spectacle lens+1 diopter has a focal length of 1 meter and 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.
Winter it is good period to watch the sky. In winter you can see many stars and planets, as well as the Milky Way. Milky Way very beautiful (visible only in a clear sky). It is visible to the naked eye. In a clear sky, excluding artificial satellites visible in the sky, the ISS (International Space Station) can be seen with the naked eye. She looks like a moving light source high intensity, similar to Venus. The author of this homemade product observed all this with his own eyes and after that decided to purchase a telescope, but discovered that it was a very expensive pleasure. So he decided to make a simple home telescope. To make it you will need PVC pipes and lenses.
Step 1: Theory
A telescope is used to see a distant object that is not visible to the naked eye. The telescope zooms into a specific area. The field of view is reduced and focused on a small part, resulting in a more detailed viewing experience.
The main components are a large objective lens and a small eyepiece. The lens has a large diameter, which increases the ability to collect light. More light means a clearer image, and there is a long focal length for a magnifying effect. The eyepiece has a smaller diameter and shorter focal length (to provide high magnification). The lenses are convex.
The lens converts a parallel beam of light from infinity (at a far distance) to a single point. The eyepiece diverges from convergent light because our eye needs parallel rays (our eye has a convex lens). Using this arrangement we get an inverted image. For sky viewing, inversion is not a problem. The scaling effect (increase) is determined by the given equation:
magnification = focal length (lens) / focal length (eyepiece)
A telescope works by refracting light rays. It has chromatic abrasion problems caused by different colors focus at different points, so bright objects appear rainbow-colored. This problem is reduced in a reflecting telescope. It uses mirrors, so refraction does not work. But a reflecting telescope is difficult to build, so we will create a refracting telescope.
This telescope does not have higher magnification. It is made more for educational purposes, so it has disadvantages.
Step 2: Necessary materials and tools
Convex lens 8.5 cm diameter
Lens with focal length 27 cm
Eyepiece from an old binocular, diameter 3.5 cm, length 5 cm, focal length 2 cm
PVC pipe with a diameter of 100 mm and a length of 25 cm
PVC pipe with a diameter of 50 mm and a length of 8 cm
PVC reducer (adapter) from 100 mm to 50 mm - 1 pc.
PVC plug, diameter 50 mm - 1 pc.
Screws (as many as needed)
Basic tools and materials are shown in the figure.
Step 3: Preparing Materials
To assemble a homemade product, you first need to prepare all the necessary materials:
Lens parts
1. Cut a piece of PVC pipe with a diameter of 100 mm and a length of 17.5 cm using a hacksaw blade.
2. Cut a piece of PVC pipe with a diameter of 100 mm and a length of 2 cm using a hacksaw blade.
3. Cut 3 pieces 2 cm long.
4. Peel and trim edges using a small knife.
Eyepiece parts
1. Take 8 cm PVC pipe.
2. Peel and trim edges using a small knife.
3. Take a 5 cm end cap and drill a hole in its center using a drill press or alternative method.
4. The hole size is 2.8 cm (using the diameter of the binocular eyepiece).
Step 4: Fixing the Lens
First you need to fix the lens in a PVC pipe. The lens has a smaller diameter than PVC pipe. Therefore, to reduce the diameter, it is necessary to place a 2 cm long piece of PVC into the pipe. The lens is placed 2 cm inside the tube to reduce glare from side lights entering the telescope.
1. First, cut PVC into a small width and remove a part to secure this piece inside the PVC pipe (2 cm inside from the edge).
2. Then another piece of PVC is cut and some part is removed to fit the first piece placed.
3. Make sure the piece is 2cm away from all positions, and then secure it with screws (screws do not go inside the PVC pipe).
4. Then place the lens and secure it using other small PVC pieces and screws. This is shown in the photo.
5. Then attach the gearbox to it. Use screws to secure the structure if it becomes loose. Make sure the screws do not penetrate the PVC.
6. Be guided by photographs if it is not very clear. The images are taken step by step.
Step 5: Fixing the Eyepiece
1. Attach the eyepiece to the hole in the end cap using screws and metal strips.
2. Make sure the screws do not penetrate inside the eyepiece.
3. All actions are shown in the photo.
4. Connect a PVC adapter (reducer) with a diameter of 100/50 cm to the end cover and secure it with a screw.
Step 6: Assembling the Telescope
Make sure that the 100 cm pipe moves freely inside the gearbox.
If necessary, sand the surface of the PVC pipe.
The movement of the PVC pipe in the gearbox is used to accurately focus the telescope.
To adjust the focus, look at a distant object through the telescope and find a clear image. The sharp image point is the focus point. Secure this position with a screw to secure the telescope at its focus point.
Step 7: Tips for Selecting Lenses
The telescope is unfairly considered a difficult device to use and manufacture. This is a normal attitude towards devices that seem incomprehensible. But we assure you that it is possible to do it yourself. Even in a couple of hours.
We will make a telescope with magnification from 30 to 100 times. There are only three telescopes in this range, and they are the same, except for the differences in lenses and tube length.
Required:
- Whatman.
- Glue.
- Paint or ink.
- Optical lens 2 pcs.
The easiest telescope for beginners with 50x magnification. Let's start with it.
Making a lens
We roll whatman paper into a 65 centimeter pipe. The diameter of the pipe should be slightly larger than the objective lens. If the lens is spectacle, the diameter of the pipe will not exceed six centimeters. Inner side Paint the sheet black.
Now the sheet should be secured with glue. We attach the lens inside the pipe using jagged cardboard, as shown below.
- Lens from the lens.
- Eyepiece lens.
- Fastening.
- Lens tube mount.
- Add. lens.
- Diaphragm.
Making an eyepiece
A lens from a binocular will be suitable for the eyepiece. The focal length will not exceed 4 centimeters. You can check this in a simple way. Place the lens under an external light source (even the Sun) and project the light onto the sheet. You need to make such a distance that the rays passing through the lens are collected at a small point, this will be the focal length.
Roll the sheet into a paper tube so that the lens fits tightly into it. This tube is then secured to a larger diameter pipe using jagged cardboard circles.
That's it, the telescope is ready. It has one drawback - objects in it will be reflected upside down. To avoid this, you need to add another four-centimeter lens to the eyepiece tube.
A telescope with thirty-fold magnification is made in the same way, at the same time a lens of a couple of diopters is added and the length is increased to seventy centimeters.
100x magnification differs from the thirty-fold lens only in that the lens is two half diopters larger and two meters long. Through such a telescope you will see the Moon in full view, and Mars and Venus will appear the size of a pea.
This length and small lens size may cause rainbow coloring, which you can remove with aperture, installed at the focal point. This will reduce the brightness of the image, but there will be no rainbow coloring, called diffraction.
Remember that a two-meter telescope under the weight of the lenses can bend, that is, he needs wooden supports.
So you've created a telescope that will ignite anyone's love of astronomy.
This article is intended for those amateur astronomers who have already played with binoculars and a refracting telescope, looked at the phases of Venus, the rings of Saturn and the moons of Jupiter, and want something less boring and more stunning. For example, 1000x with a huge lens. It is impossible to do this with lenses alone: they produce so-called chromatic aberration, which manifests itself in the form of rainbow halos around objects, the stronger the stronger the magnification of the telescope.
Therefore, the task arises to collect homemade reflecting telescope, that is, a telescope on mirrors. In its simplest form, it consists of two mirrors (objective and diagonal) and one eyepiece lens.
Where to get it
The main mirror-lens of a reflecting telescope is its most important and critical part. And it is also the most difficult to manufacture. Finding a ready-made mirror of this type is almost impossible.
Although there is one way: you can make this from a concave or convex-concave lens. Find the largest concave or convex-concave lens you can find. It is important that the focal length be as high as possible, and, therefore, the concavity as small as possible: from too powerful concave lenses, not a spherical, but a parabolic shape is required, and this is a completely different deficiency that cannot be improvised in any way.
The most reliable calculation is to find a plano-concave one with a diameter of 10-12 cm and an optical power of 1 diopter. Look for it in optical stores. Thus, a homemade telescope of 1000x will not work, but you can do something with it.
Silver plating using chemistry
Then you need to do silvering to get a mirror. Prepare a solution called Tollens' reagent. In order to prepare this reagent, you need: silver nitrate (lapis), caustic soda (caustic soda) and ammonia solution.
This reagent kit also includes formaldehyde (formaldehyde solution). Dissolve 1 g of silver nitrate in 10 ml of water, and 1 g of sodium hydroxide in another 10 ml of water. Mix these solutions, a white precipitate should form. Add ammonia solution until the precipitate dissolves. This solution is Tollens' reagent.
To use it for silvering, you should pour it into the concave part, which has previously been thoroughly cleaned of any contaminants. If the concavity is very weak, you should make a barrier of wax or plasticine along its edge.
Having poured the reagent, you should begin to add formaldehyde to it in frequent drops. Soon a film of silver will form and it will turn into a concave mirror. Keep in mind that Tollens' reagent does not have a long shelf life; it must be used immediately after it is prepared.
There are also ways to make a concave surface yourself, first of all - grinding the concave surface on glass circles. However, these methods are too complicated and are not recommended for use by beginners.
A diagonal mirror should be made in the same way as a concave one. It should be perfectly straight; For its manufacture, the flat side of any plano-convex or plano-concave is suitable.
Telescope assembly
Now you can start assembling your homemade one. You will need a tube exactly the length of the focal length (if you used a 1 diopter plano-concave lens for manufacturing, then take a tube 100 cm long, +0.5-1 cm adjustment for thickness).
The pipe should be open at one end and closed at the other, and painted inside with the blackest paint you can find. The diameter of the pipe should be 1.25 times the diameter of the refractor mirror; if you used a lens with a diameter of 100 mm to make it, take a pipe with a diameter of 125 mm.
Attach the lens mirror to the bottom of the pipe, exactly in the center. To make it convenient to do this, it is better to provide a removable bottom. You can attach the lens to the bottom, for example, with superglue.
Make a hole closer to the open end of the pipe. To calculate the desired position for the hole, measure its radius from the open end of the pipe. This is where the center of the hole should be. The eyepiece will be fixed in this hole (perpendicular to the pipe).
It should hang on the optical axis at an angle of 45 degrees. If the angle is maintained correctly, then when you look through the eyepiece you will see the image. If you don't succeed the first time, experiment with the angle.
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) dioptres. 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 it? 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, it is necessary 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!
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