Universe & FixBot
FixBot
Hey Universe, ever tried building a telescope from scratch? I found some cheap parts that could give us a decent view of the moon—want to dive in together?
Universe
That sounds intriguing, and a telescope could be built from what you have. First we’ll need to check the focal length of the lens or mirror, then align the optical axis precisely. Let me know what parts you have and we’ll map out a step‑by‑step plan.
FixBot
Got a few spare things around—old CD for the primary, a cheap plastic tube from an old phone charger for the focuser, a bit of aluminum foil for a secondary mirror, some duct tape, and a ruler to measure. We can just glue the foil on the CD, slide it into the tube, tape the whole thing tight, and use the ruler to eyeball the focal point. Sound good?
Universe
Using a CD as a primary mirror is a clever hack, but the curvature isn’t right for a good focus. The foil secondary will flare the image and the plastic tube won’t keep the optical axis straight. It’ll work as a crude experiment, but for a decent view of the Moon we need a proper parabolic surface and a stable mount. Maybe we can repurpose a cheap lens from a camera instead of the CD, and a piece of thin metal for the secondary. If you’re up for it, I can walk you through a more reliable build using the parts you already have as starting points.
FixBot
Yeah, let’s swap the CD for that camera lens and grab a thin aluminum strip from a foil packet for the secondary. Just slide the lens into a sturdy cardboard tube, tape a mount around it, and angle that strip just a couple of degrees—tweaks later. I’ve seen this on r/DIY; the focus comes out surprisingly good when you test it on the moon with a simple night sky. Ready to get those parts hunting?
Universe
Great idea—camera lenses are surprisingly good primaries if you choose one with a decent focal length. Grab a clear lens from an old DSLR or compact camera, then cut a thin strip from the foil, about 3–5 mm wide, to act as the secondary. Slide the lens into a sturdy cardboard tube or even a metal pipe, then tape a small mount at the back so you can rotate the secondary by a few degrees. Use your ruler to measure the distance from the lens to the focal plane and adjust until the moon looks sharp. Let me know what you find, and we can fine‑tune the alignment together.