The two are not the same. In the first case, Deep Sky Astrophotography, we are focused on the heavens without any identifying landscapes.
In the case of Landscape Astrophotography, we are including an identifiable earth bound object in our photos of the heavens above. This kind of photography is also known as nightscape photography.
The techniques used differ a little for each, but are related, as are all photographic skills. There is more astronomy in Deep
Sky work, but more relatable imagery in nightscape photography, at least in my opinion.
The Blog goes in greater detail on many different aspects of each of these types of photography. The rest of my life could be spent on studying all of this, since earth and space dominate everything.