NASA - National Aeronautics and Space Administration, Excerpt from the Optics: Light, Color and Their Uses Guide, Follow this link to skip to the main content, http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/Optics.Guide.html. In the pack you can find 3 achromatic lenses; one for the objective and two for an almost perfect ploessl-eyepiece, and some cardboard supports for it (I haven'n used it, anyway). The largest reflecting telescopes currently have objectives larger than 10 m (33 feet). The collimating eyepiece has a pinhole sight that helps you determine if the optics are properly aligned with the tube. Make an Eyehole. Use achromats (well, this is not so easy, but no doubt, the best way.) A simple lens never will produce razor edge-like image, but the Moon can be observed with a scope built with this objective lens. Gaff, Gaft, whatever. This is going to be really helpful when you focus your telescope. Hopefully, your internal diameter and larger lens diameters match up pretty nicely. Simple lenses are useful for astronomy with only these very limited ways.Sorry, I was too long, I'm afraid. on Introduction, NIce work, my parents' generation made scopes like this in my homeland, in Hungary. For the smaller lens, cut a hole into a pill bottle cap or some other plastic thing that fits nicely into the smaller diameter PVC. I encourage anyone interested in building a telescope to check out my process and modify it as they see fit! But, you know, there are not wonders...1. Make sense? Never use plastic ones, the plastic is for ONLY eye glasses, believe me, its refracting errors are horrible over the focal lenght!2. Using the smaller pipe that you bought, flatten the tape against the inide of the PVC by sliding the small pipe down the larger one. This is more like a parts list rather than an instructible. Could you please tell me what should be the ratio of diameter of both lens? If you're using a lens from a magnifying glass, get it out using the exacto knife and dremmel. The smaller diameter PVC fit nicely inside the larger one, and, with a little finessing, the lenses fit in each. This I really nice and proper instructable and I am looking forward to make a telescope. This old DIY-community was working as a virtual club in Hungary, when the people were under terror by the communism, and almost nobody had enough money to get normal scopes to observe, but a lot of children and adults wanted to look into Universe instead of their misery. Finally, you're going to want to tape the rim of the smaller tube to ensure it doesn't fall into the larger one. Thread a piece of gaff tape down the pipe and affix it to the edge on opposite sides. javascript is enabled. Did you make this project? Your browser or your browser's settings are not supported. 2 parts, different glass materials, with sophistically designed curves and other tricks) may be too expensive for an amateur astronomer, so here are the tricks to improve a bit the imaging of these simple and cheap lenses. Powerful Telescopes, Big Rewards. Building this for the science fair, what did you glue the bigger lense, to and where did you stick the paint cap. 5.2 Making the tripod legs For a good small scope for cheap is available here - this is a kit for children, I have built it in a school (as a classroom-activity leader teacher), and its imaging is very cool, but the joy of the DIY making is remains. This may be useful when looking at Moon, but the dim galaxies and nebulae won't be seen with a scope with an objectiv diameter under 70-80 mm.3. Gaffers Tape. Ultimately, I decided that I'd tape the inside of the larger pipe. As of late, I've become very interested in space, stars, galaxies, and the universe. The smaller diameter tube should be about double the size of the larger tube that you just cut off.