A 114 mm mirror, a meter of 5-inch PVC pipe, and a Raspberry Pi Zero 2W are all it takes to beat a commercial 50 mm aperture telescope. Builder Makestreme published the full design on Instructables under the name Astra, replacing the traditional eyepiece entirely with a Raspberry Pi Camera Module 3 mounted at the focal point of the 900 mm reflector.
The system runs on a single 18650 lithium-ion cell stepped up to 5 V, making it fully portable. A Python web server hosted on the Pi streams the live camera feed over a local network and exposes controls for brightness, exposure, and gain. Aiming is handled through SkyMap and SkEye on a phone. The mirror mount and collimation hardware are 3D printed. The original article is worth reading for the collimation process and the optical math behind matching pipe length to focal length.
This build matters because it inverts the telescope design problem. Instead of chasing better glass, Makestreme replaced the analog output with a digital sensor and a network interface. The tradeoffs between sensor size, focal length, and field of view are detailed in the source, and they apply directly to anyone repurposing surplus optics.
[READ ORIGINAL →]