Hardware
Telescope kits
The two parts that are hardest to source, sent to educators who ask.
Most of a horn telescope comes from a hardware store. Two pieces do not: a software-defined radio dongle, and a low-noise amplifier tuned for the 21 cm hydrogen line.
If you are an educator or a community organiser who is held up by access to that equipment, you can ask for a starter kit. Fill in the form with your shipping details and a short note on what you plan to do — or have already done — with your students or your group.
Kits are sent while supplies last. If they have run out, everything in the lessons still works with parts bought directly; the Telescope Hardware Setup module lists what to get and where.