How to make a telescope
Things You'll Need: * Cardboard Tubes * Glue Guns * Convex And Concave Telescope Lenses 1. Step 1 Acquire a pair of lenses - a large convex lens and a small concave one. (Convex lenses are thicker in the center than at the edge; concave ones are thinner in the center.) 2. Step 2 Find two cardboard tubes that will allow one to slide inside the other. 3. Step 3 Figure out how far apart the lenses should be by looking through the smaller lens while holding the larger one out in front of you. When you can focus on an object in the distance, measure how far it is between the two lenses. 4. Step 4 Double that measurement. The length of the two tubes should be about this long. 5. Step 5 Fasten the larger lens on one end of the wider tube. Hot glue is good for this. 6. Step 6 Mount the smaller lens at the opening of the smaller tube. This is the eyepiece. 7. Step 7 Build a gasket from cardboard or Styrofoam if the tube opening is larger than the lens. 8. Step 8 Make sure the lenses line up with each other. The centers should be in the centers of the tubes and the lenses should be parallel with each other. India Becomes Universal Leader In Space www.freewebs.com www.freewebs.com www.freewebs.com www.freewebs.com
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US $34.99
very useful , thank u
thanks
If you put the lens on the table the push the tube onto it then it should be flush at the end. much easier and less fiddly.