The quantity we have in earlier chapters called "radiance" was used to describe the brightness of an extended radiating surface, and the new term "specific intensity" can equally be used in a similar ...The quantity we have in earlier chapters called "radiance" was used to describe the brightness of an extended radiating surface, and the new term "specific intensity" can equally be used in a similar context. More often, however, you may need to imagine yourself embedded somewhere within a stellar atmosphere and you are looking around to see the watts per square metre per steradian arriving at you from various directions.
