The Horn Antenna seems to be a favorite goto and for good reason.
All you need is Aluminum flashing 20″x10, a empty paint thinner can, aluminized HVAC tape, N-to-SMA adapter, N Connector, Nooelec SDR and LNA. The cost would be roughly around $100.
The software can be either HDSDR or SDR#.
Will update after making this myself and testing it. More to come…
To build your own Amateur Radio Telescope, you will need a few item to get started.
You will need:
Antenna --> LNA --> Bandpass filter --> Power Injector (Bias Tee) --> SDR Dongle --> PC
Software used can be SDR# or a selection from https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/ ,
also need to download Radio Eyes to capture a Bell curve like the one below.
To read into Radio Astronomy deeper, here is a PDF book from Society of Amateur Radio Astronomers (SARA): Sara Beginner Booklet