Telescopes are tools for exploring our world and other worlds.
Telescopes spark the imagination. They bring distant worlds near, allowing us to watch birds without disturbing them and see other planets without needing a spacesuit. There are dozens of types of telescopes, but they all are designed to collect a lot of light, then make it easy to look at the image created by all that light. The basic design rule is to focus distant light down to a point with an objective lens or a primary mirror, then magnify that point with an eyepiece.
Instructions
Making a Keplerian Refracting Telescope
1. A demonstration telescope is easy to make from inexpensive parts.
Put the small 50-mm focal length lens in the adapter tube.
2. Put the 300-mm focal length lens in the large mounting tube.
3. Measure along the mounting tube a distance equal to the sum of the focal lengths for the two lenses, 350 mm.
4. Insert the adapter tube in the mounting tube so that the small lens is 350 mm from the large lens.
5. Look through the telescope and gently slide the adapter tube to focus the telescope.
Making a Newtonian Reflecting Telescope
6. Not every reflecting telescope needs a mirror this size. A home-built Newtonian is a little more manageable.
Insert the large mirror at one end of the mounting tube, reflective side facing the inside of the tube.
7. Measure 335 mm from about the center of the mirror and cut a hole in the side of the mounting tube large enough to fit the small lens adapter tube.
8. Although small mirrors are easier to build with than monsters like this one, reflecting telescopes are not that easy to assemble.
Place the small flat mirror mount at an angle of 45 degrees so its center is at the same height as the hole for the small mirror mounting tube.
9. Insert the 35-mm focal length lens in the adapter tube, then put the adapter into the hole on the side of the mounting tube. Slide it slightly back and forth to focus the telescope.
Tags: mounting tube, adapter tube, focal length, focal length lens, length lens, lens adapter