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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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By: SFisher
Date: Feb 03, 2015

Where are you supposed to find the lenses? I am hoping
that I can use this for a science project, and without lenses
it might be a little hard.

By: ishan
Date: Jan 30, 2015

from where u got the lenses

By: thirisa
Date: Jan 22, 2015

this information was very useful so i was able to make a telescope

By: laura
Date: Jan 21, 2015

does someone have a photo of a completed telescope that they might be able to send?
also, any additional tips you might give in addition to these instructions?
thank you!

By: ankush sarmah;INDIA
Date: Jan 16, 2015

thanks ...It has helped me so much

By: Isac
Date: Dec 22, 2014

It’s useful. Thanks!

By: Arun
Date: Dec 19, 2014


By: laishram martish
Date: Dec 11, 2014

its very interesting and useful to me

By: Sajid Fardin
Date: Nov 23, 2014

Where can I find the 150 mm and 500 mm double convex lenses?

By: ff
Date: Nov 17, 2014

very bad useless