Here winter season starting now. The memories of winter is that, It is the good period for sky watching. In this season we will see a lot of stars and planets also the milky way. The milky way is very beautiful( it is only visible in clear sky). It is seen by naked eye. In the clear sky I had a hobby, which is that to take the no of artificial satellites seen in the sky, four times i got the golden chance to see the ISS( international space station) with naked eye, it is seen like a moving high intensity light source, seems like Venus. It is an unforgettable moment in my life, that time I think that I need a telescope. Because if I had a telescope , I see the planets and stars very closely. But I found that, that are expensive. So here I am trying to make a simple home made telescope. It uses some PVC pipes and Lenses.
My project mission is to explore the infinite universe to every one, I think that a telescope is the key to explore the wondering universe. Telescope is the basic tool for study the far objects.
I believe that it is useful for anyone which interested to explore the universe. If any one can doubt about sky, please enter to NASA website, they tell all about sky.
Step 1: Theory
Telescope is used to see far object which is not seen by naked eye. The telescope zoom a particular portion. Area of view decreases and focus to a small area which results more detailed view.
The main components are a large Objective lens and a small eyepiece. Objective lens has a high diameter which increase light gathering capacity, more light means more clear and also have a high focal length which ensure the zooming effect. The eyepiece has a lower diameter and a lower focal length(to ensure high zoom). The lenses are convex. The objective lens Converges the parallel manner light ray from infinity( at far distant) to a single point. The eyepiece diverges the converged light because our eye need a parallel like rays( Because our eye have a convex lens). By using this arrangement we get an inverted image.For seeing sky inverting is not a problem. The zooming effect (magnification) determined by the given equation,
magnification = focal length (objective lens) / focal length (eye piece)
Here the telescope worked based on the refraction. So it is called REFRACTION TELESCOPE . It have problem chromatic abrasion, which is causing by the different color is focused at different points , so bright objects seem like a rainbow color. It is decreased in reflecting telescope. There use the mirrors instead of lens so refraction not in action. But reflecting telescope is difficult to build so we try to create refracting telescope. But for beginners it is good. Here our telescope not have much more magnification. It is a sample project. It is done for study purpose, so it have some problems.
I believed that it is helpful for some ones.
Step 2: Materials & Tools Needed
The whole materials needed only around 1000 Indian rupees. Also needed some tools. These are common tools. You choose your tool choice. Because it is your comfort.
- Convex Lens 8.5 c.m dia. , 27 c.m focal length (objective)
- Eye piece of an old binocular 3.5 c.m dia ,5 c.m length, 2 c.m focal length
- PVC pipe 4" - 25 c.m
- PVC pipe 2" - 8 c.m
- PVC reducer 4" to 2" - 1 nos.
- PVC 2" end cap - 1 nos.
- Screws (as your need)
The tools and materials are given in the figure.
So lets start the project...............
Step 3: Setting Up of the Material
For the project first we prepare all the material needed. That is the cutting and finishing of the parts. The steps are given below.
Objective lens part
- Cut the 4" PVC at a length of 17.5 c.m using hacksaw blade
- Cut the 4" PVC at a length of 2 c.m using hacksaw blade
- Cut 3 pieces of 2 c.m long
- Clean and finish its edges using a small knife
Eye piece lens part
- Take the 8 c.m PVC pipe
- Clean and finish its edges using a small knife
- Take the 2" end cap and drill a hole at its center using a drilling machine or alternative method
- Hole size is 2.8 c.m ( use your eye piece diameter)
For drilling hole I have no suitable drill bit so first I drill a hole using small bit and then it is enlarge by using an old cutting pliers and drill machine. These all shown in the figure.
Step 4: Fixing the Objective Lens
First we trying to fix the objective lens in a position. The objective lens is smaller diameter than the PVC pipe. So it is loose in the PVC pipe. So we place the 2 c.m length PVC inside the pipe to reduce the diameter. The Lens place a 2 c.m inside to reduce the side lights entering to the telescope.
- First cut the small length PVC and remove some portion to fix it inside the PVC pipe (2 c.m inside from edge)
- Then other PVC piece cut and remove some portion to fit inside the first piece placed
- Similarly 3rd piece
- Ensure that the piece is 2 c.m inside from all position and then fix it by using screws (screws not penetrate into inside of PVC pipe)
- Then place the Lens and fix it by using another small PVC pieces and screws. It is shown if the images. You fix it in your methods.
- Then place the Reducer to it. And use a screw to fix it in the case of loose. Ensure that no screws penetrate into the PVC
Observe the images if in the case of doubts. The steps are clearly visible in the images.
Step 5: Fixing the Eye Piece
I use an eye piece from old binocular. Other wise you use a convex lens of 3-4 c.m diameter and about 4 c.m focal length and fix it like the objective lens fixing method shown in previous step.
- Fix the eye piece to the end cap hole by using screws and metal strips
- Ensure that no screws penetrate to inside of eyepiece
- All are given in the figure
- Connect the 2" PVC to the end cap and fix it using a screw
Observe the images in the case of doubt
Step 6: Assembling of Telescope
It is the final step.
- Smooth the 2" PVC surface to ensure that it is freely moving inside of the reducer.
The PVC in and out movement in the coupler used to precise the focus of the telescope.
For fixing the focus observe a far object through the telescope and find the clear image. The clear image point is the focus point. by using a screw to fix the telescope at its focus point.
See the images for how it look like.
Finally we done the TELESCOPE project !!!!!!!!!!!!!!!!!!!
Step 7: YOUR DESIGN
This is my design. Because I use the lenses which is available at my near city. I am not believed that it is available at your city. So, you need your design. So I give the tips for the Telescope design in given. You choose the available lenses in your city but ensure that it is satisfy the given design conditions.
Selection of objective lenses ( convex lenses)
- Use larger diameter from 8 c.m to 16 c.m . Larger diameter ensure the high light gathering capacity which will increase the clarity of the image.
- Use high focal length lenses from 30 c.m to 100 c.m. High focal length means high magnification which means high zooming. Refer the theory step.
Selection of eye piece ( convex lenses)
- Use small diameter. about 2 c.m to 4 c.m. Because it is nearer to the eye.
- Use small focal length about 2 to 10 c.m. Which ensure high magnification.
Selection of PVC lengths
- The objective lens PVC is about 70% of the total focal length.
- The Eye piece PVC length is about 40% of the total focal length.
- Adjust the lengths by yourself to ensure the clear image. It is a rough calculation.
I believed that it is help you to design yourself. Making of your design is more interesting than the copy of my design. It is only a sample model. You try your level best.
Step 8: Conclusion
Are you hurry up to observe the sky. Wait for a clear night sky.
It is work well. I saw a lot of stars by this which is not visible by naked eye. It is very interesting. It is my first experience. I wondered. It is working........ This is my first TELESCOPE and it is my first telescope watch.
I believed that you are also wondered like me. Try it at your home and find the unknowns in the deep sky.
My next plan is to hunt the moons of the astern and Jupiter. You tried it yourself. Once you start the sky watch , you never stop it. Because it is very very interesting.
I planed to create a stand (tripod) to fix the telescope. I publish it soon.
Please ask me to for any doubts.
Runner Up in the