I want to tell you about my experience of amplifying a toy telescope
from such a cheap Chinese-made children's plastic kit.
From the maximum declared for him 40x to 100 times. That is, more than doubling the magnification, to the level of inexpensive entry-level telescopes. That will allow to observe in more detail not only the Moon, but also other objects.
Moreover, additional financial costs can be considered insignificant.
And, if you're lucky, and you happen to find suitable glasses, then you won't have to visit shops at all.
So, to achieve all of the above you will need :
1. Children's set “Microscope and telescope”.
(They cost in online stores from 2000 rubles, but I got a used one for 300 rubles, according to an ad on a flea market website. I think that if you don't have one, then you shouldn't buy for a large amount ).
2. 1 spectacle lens at +1 diopter.
(You can buy it in optics stores. The cost starts from 200 rubles and more, depending on the manufacturer. For the experiment I took an ordinary polymer one for 200 rubles. But, if finances allow, you can choose a higher quality product, for example, with an antireflection coating True, I do not know how much this will fundamentally improve the characteristics of this telescope, but then you can also cut off the lens to the required diameter, which will further facilitate the work.
Or, as the name suggests, you can look for suitable optics among the old UNNECESSARY glasses. Where you get them is your concern :). But how to determine that the lens is right for us, I'll tell you below.)
3. Cardboard pipe with a diameter of 45 mm or 55 mm; length 600 mm and wall thickness from 3 mm.
(Various rolled building materials are wound on such. You can ask, for example, where they sell plastic films)
4. 2 coffee paper cups. One smaller – 70 mm in diameter. And the second one is larger – 90 mm in diameter of the upper part (not necessary if you are using a lens from old glasses).
5. Furniture screw with a diameter of 6 mm and a length of 70 mm.
6. 3-4 nuts of any size and inner diameter from 6 mm or an old bearing or all together (pick up empirically).
7. Plastic bottle (where without it?).
8. A piece of foam 70×70 mm and 10-15 mm thick.
Tools for work will be like this:
1. Glue gun.
6. Masking tape (or ordinary).
Well, having admired the tiny moon and finally making sure that we are not quite satisfied with the power of our telescope “out of the box”, we proceed to upgrade it.
First, consider the option that you did not have old unnecessary glasses and had to go to optics store and buy just such a +1 diopter lens, 70 mm in diameter.
+1 diopter means that this is a converging lens with a focal length of 1 meter. That is, if you pass sunlight through it, then the transmitted rays will be collected in the smallest and brightest point exactly one meter from the glass.
(What happens if you hold this bright dot over some piece of paper or other flammable thing longer, I think you yourself know. And if you don’t know, then I inform you that smoke may go and a charred hole may form. For this reason, never look on the Sun through optics without special darkening filters that reduce the brightness by as much as 99%!).
But it is possible to use not only the closest star to determine the focal length of the lens (it happens that clouds cover it at the wrong time). Any light source that is sufficiently distant will do. A light bulb or a window. And where the image behind the lens appears as clearly as possible, there is the focal plane.
So, we made sure that our lens has a meter focus.
For your information, the lens originally installed in the telescope from the kit has a focal length of only 40 cm. And that is exactly what we will change.
To do this, unscrew the telescope tube from the tripod.
Then, detach the black plastic cap that protects the lens from side light. Be careful. It is glued, so you will most likely have to use a knife to “push” the nozzle towards the exit from the pipe.
Next, you need to remove the “standard” lens.
It looks tiny.
However, this is a perfectly normal diameter for instruments of this level. And no matter how upset it may be, we also have to limit the diameter of our 7 cm lens (more on that later). We will improve the telescope not due to the larger lens size, but due to the larger focal length. Indeed, it is this value, or rather, the ratio of the lens focus length to the eyepiece focus length, that determines the magnification of the simplest refractor telescope. That is, the longer the lens (the longer the tube) with the same eyepiece, the greater the magnification. We are not going to change the eyepieces (yet), we will assume that they suit us.
Of course, this is not the only criterion that determines the quality of the image obtained by the telescope. But the purpose of this review is not a lecture on telescopic construction, but a description of how a small refinement can help to get something interesting on the basis of cheap toys.
You should not throw away the removed lens, it is quite suitable for use as a regular magnifier (or, perhaps, you will want to return it back).
Since the new lens is longer focal length, we need to extend the telescope just as much as the new focus is longer than the old one, that is
100 cm – 40 cm = 60 cm.
This is exactly the length that needs to be cut off the cardboard tube.
Only one thing depends on the diameter of the cardboard pipe you have – you will insert the plastic part into it without the black nozzle, which was separated to remove the lens (if you have a 45 mm pipe) or together with it, if the pipe diameter is 55 mm.
In the second case, you may have to sharpen the cardboard from the inside with a knife in order to slightly increase the inner diameter
and also make the pipe 4 cm shorter, that is, instead of 60, cut off 56 cm.
After we have prepared the cardboard tube, we proceed to install a new lens on its end. To solve this problem, I decided to use coffee cups (I really liked the idea).
One (whichever is smaller) will serve as a support for the lens, and the second (larger) will protect.
To put a smaller glass on the pipe I cut out the bottom of it
And he made 8 cuts about 5 mm deep along the perimeter from the bottom side.
Then I checked that the pipe now fits freely into the cup
Then I got a small piece of 7×7 cm styrofoam (if you couldn't find another, you can donate part of the package from the kit).
And I cut out a ring with an outer diameter the same as the upper edge of a small glass, and with an inner diameter, like the outer diameter of a cardboard tube.
Moreover, I cut the outer edge of the ring with a slight slope to the smaller side, that is, under the cone. In such a way that after trimming it fits tightly into the inside of the glass.
Having put the glass on the pipe so that its edge and the edge of the pipe were at the same level, I inserted a foam ring between them, ensuring in such a simple way the fixation and alignment of the pipe and the glass relative to each other.
To prevent the glass from moving, I wrapped masking tape around the junction of the glass with the pipe.
Now you can attach the lens. I laid it directly on the glass, with the convex side outward, placing the lens as evenly as possible along the edges.
Then fixed it with tape.
Remember to wipe it with a soft cloth before attaching it to remove dust and stains. Especially from the concave (inner) side. Since access to it after commit will be limited. And, if dirt remains, you will have to unwind the tape to carry out cleaning.
< img class = "aligncenter" alt = "Modification of the toy telescope from the children's kit to a magnification of 100 times" src = "https://usamodelkina.ru/uploads/posts/2021-01/1611750303_35.jpg"/> Next, you can install lens protection from side light (which is very important in urban conditions). For this you need a bigger glass.
I also cut out the bottom of a large glass and just kind of continued with it the cone of a small .
(In the absence of paper cups, the necessary cones can be made independently from a sheet of thin cardboard using this printout
It is suitable for both cones, large and small)
I do not recommend sticking the protection, because in the future, you may need to clean the lens from dust or accidental debris. And to get to it, it will be easier to unwind the paper tape than the glued parts.
In the resulting structure, from the end opposite from the lens, I inserted a “native” plastic part with an eyepiece. As I already mentioned, if your pipe is 45mm, then insert it directly, without a black nozzle,
and if 55 mm, then with the nozzle.
The significantly lengthened base of the telescope caused a regular shift of the center of gravity towards the objective and the telescope began to tilt forward.
Therefore, I had to slightly offset the area of the tripod connection. For this, I first determined the approximate position of the point where the elongated tube balances in the air without falling (with the eyepiece extended to the middle of the stroke).
And with the help of hot melt glue I attached a plastic bottle cap to the new center of gravity.
< a href = "https://usamodelkina.ru/uploads/posts/2021-01/1611750293_45.jpg" rel = "prettyPhoto"> Then you need to cut off the neck from the same plastic bottle and glue it to the rotating head of the tripod. Exactly to the place where the telescope was previously attached with a screw (for convenience, you can unscrew the screw holding the tripod head and remove it).
Despite the increase in size, the telescope is not very heavy. And after hardening, the hot melt glue copes with the task of keeping its weight. But there is a slight skew towards the pipe relative to the axis of its rotation on the tripod. So I decided to add a small counterweight to the telescope. To do this, I took a 7 cm furniture bolt with the same thread as the bolt in the telescope support.
Then, I drilled a 6 mm through hole in a cardboard tube through the center of the lid. < br> Slightly expanding the hole formed on the opposite side of the cover with a knife to the size of the bolt head, I inserted the bolt itself inside. So that he rests his hat against the inner wall, completely coming out from the side of the plastic cover.
After cleaning the inner surface of debris and removing the uneven edges of the cardboard, I sealed the drilled hole with tape so that debris would not enter the telescope in the future.
I added glue and fixed the bolt in position.
< a href = "https://usamodelkina.ru/uploads/posts/2021-01/1611750382_58.jpg" rel = "prettyPhoto"> After the glue had set, I, passing the protruding end of the bolt through the hole in the tripod head, screwed the cap together with the tube onto the neck of the bottle, creating a support for the telescope at the location of the new center of gravity.
Then I planted some nuts and an old bearing on the remainder of the bolt. Having thus built a kind of counterweight.
To fix all this, a native nut with a plastic handle, which was previously the leg of the telescope and screwed to the tripod, was perfect.
Put the tripod head back in place.
This is what happened.
And this is how it looks after painting.
Now a few words about what happens if you have old glasses with lenses (oops) +1 diopter.
Yes, in principle, everything is the same, only even simpler. Easier in the sense that you can glue the lens directly to the pipe if you don't want to bother with glasses.
A 55 mm diameter pipe is better suited for this. But you have to try to align the optical axes of the lens and eyepiece. If you position the spectacle lens unevenly, there may be severe distortion in the image when observing. You may even need to trim the tube edges a little where they touch the floating lens edges so that it fits as perpendicular to the telescope axis as possible.
Well, and then everything is in the same vein.
What lenses are suitable for amplifying such a telescope? Any plus with a focal length greater than 60 cm. Standard options are: 66, 80, 100 and 133 cm. Estimated maximum magnifications will be 60x, 80x, 100x and 130x, respectively. You can, of course, swing at 200x (the length of the pipe will be 2m), but this will require a more deliberate approach. Not always “higher magnification” = “better picture”. Alas.
The new old telescope is ready.
It remains to cut out the diaphragm.
The fact is that the longer the telescope axis and the larger the lens diameter, the stronger the various distortions caused by the difference in the angles of refraction of light rays going through the center and through the edges of the lens. This results in degradation of the resulting image despite the gain in magnification. To reduce the negative effect of aberrations, limiters are installed that narrow the telescope's entrance hole, that is, the diameter of the objective. Called apertures, and in the simplest case look like this.
That is, it is just a cardboard ring with an outer diameter equal to the lens diameter, and with an inner diameter equal to 20-30 mm. I assure you that without such a ring it will not be very comfortable to conduct observations. So it is necessary to make it. It is inserted directly in front of the lens.
You can test. And here are the first results (the photos are turned upside down for ease of perception, everything will be upside down in the telescope):
Sorry for the picture quality. It turned out that on such a toy tripod, it is impossible to avoid shaking when shooting. And even such a homemade device for fixing a smartphone on the eyepiece does not help.
But it looks a little more interesting live.
And although I did not manage to photograph the Moon with the help of an enhanced children's telescope, I managed to admire it, and, yes, it “increased in size.” The conclusion is that the result was worth the effort. It became a little more interesting to watch. It is, of course, still a toy, but we can say that it received a “second life.” Plus, I gained some experience in telescopic construction.
A small bonus .
You can also add magnification to your telescope by simply placing the eyepiece away from the microscope. This will roughly double the magnification, no design changes. It will only be necessary to compensate for the difference in diameters. But I'm afraid the result will not please you too much. The eyepiece in the toy microscope is of very poor quality. In addition, a single lens generates excessive aberrations. But the experience is interesting and can give an idea of the work of optics.
By the way, for the same reason (of poor quality) it is better to use telescopic eyepieces in the microscope from the set. And, if, at the same time, a little, by 10 centimeters, increase the base of the microscope with the help of a sheet of paper rolled into a tube, then you can significantly enhance the microscope.
That's all, thanks for reading. The question/topic is automatically published in the social. site network – follow the answers there too: