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    Home / Science projects / Make a Simple Telescope
    • Make a Simple Telescope

      Make a Simple Telescope

      Building your own telescope is a fun optical experiment and it can be used to get a better view of the moon and other distant objects.

      What You Need:

      • Two lenses with different focal lengths (We recommend 150 mm and 500 mm double convex lenses.)
      • Paper towel roll
      • 1 piece of paper or cardstock
      • Tape

      What You Do:

      1. Roll up the sheet of paper or cardstock the long way to form a tube that is about the diameter of the lens with the shortest focal length. This will be the eyepiece. Tape the edges of the eyepiece lens to one end of the tube as neatly as possible.

      2. Tape the second lens neatly to the end of the paper towel tube. Insert the empty end of the paper tube into the cardboard tube. Now your telescope is ready to be used!

      3. Look through the eyepiece and point the other end of your telescope at a distant object. Slide the two tubes in and out until the object comes into focus. You will see the image upside down and magnified. If you have trouble focusing the telescope, you may need to lengthen the tube, either by using a larger piece of paper for the eyepiece end or a longer cardboard tube (such as from a wrapping paper roll).

      What Happened:

      You have just built a simplified version of a refractor telescope. The lenses at each end work together to focus on a distant object and magnify it so that your eye can see it better. The lens on the outside tube is called the objective lens. This lens collects light from whatever you point the telescope at. The lens at the other end of the telescope is called the eyepiece lens. It takes the light that the objective lens has collected and makes it bigger so that it takes up more space on the part of your eye that allows you to see, so that when you see the image that your telescope is focused on, you see it several times larger than you can see it with your eye alone.

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    Comments




    By: Ashu pathak
    Date: Apr 30, 2017

    This is not so good because by this telescope i can see the moon and other just as 50 Rs. binocular


    By: Norm
    Date: Apr 12, 2017

    This project suggests 150mm and 500mm lenses.
    Has anybody tried using the other lenses offered (for example, 50mm) to increase magnification?
    Does it work well with other lenses, or do the other lenses distort the image too much?
    Thoughts?


    By: The GSM
    Date: Mar 02, 2016

    Does smaller eyepiece focal length result in greater magnification? So does that mean I should get smaller focal length lens for the eyepiece?


    By: Carrie
    Date: Feb 03, 2016

    My son and I just completed this lab. I have a couple of corrections you may want to consider making in your instructions. 

    A paper towel tube is too large for the lenses and a paper plug will need to be made to bridge the gap between the tube and the lens.

    Secondly, we found the lens with the longer focal point (500mm or 50cm) worked best as the eye piece. We had to place the 150mm or 15cm lens at end of the tube facing the sky.

    This was an interesting lab and required quite a bit of patience to put the lenses into the tubes, but it was worth the small amount of money to purchase the lenses.


    By: ashish
    Date: Jan 17, 2016

    Both lenses are double convex lens or either outer or eye piece lens????


    By: Mayank
    Date: Dec 06, 2015

    We need to take the diameter of the lenses different?


    By: ANILGHST
    Date: Oct 12, 2015

    it is very easy and useful. thanks


    By: Nellie kamwendo
    Date: Oct 10, 2015

    This is great, i have my own telescope now…...thanx


    By: himanshu malik
    Date: Sep 04, 2015

    i never think telescope can be made in a such wayway i thank to bruno,copernicus and Galileo


    By: shivang
    Date: Aug 09, 2015

    can u please tell me…how far can i see in space by using this telescope?....please reply as fast as possible.

    [HST adds:  You can read about magnification and focal length of telescope lenses here:  http://www.hometrainingtools.com/a/selecting-a-telescope-science-teaching-tip  Hope this helps!]