Units of radiation
 Short Topical Videos
- Photon Buckets: How (Radio) Telescopes Receive Power (by Aaron Parsons)
- Units of Radiation (by Zaki Ali)
 Main Questions
- What is the point of talking about specific intensity?
- Why use the Jansky? What does flux density mean?
- Which quantities depend upon observing conditions and which are intrinsic to the source?
The NRAO Essential Radio Astronomy course explains this pretty well in their chapter on Brightness.