Atmospheres are omnipresent and they are frequently used in everyday language. Yet, when do we perceive atmospheres and how can we explore them? The concept of atmosphere extends aesthetics to aisthesis and comprehends perception as a relation bound to the present and with regard to others. In this context, the astonishing atmosphere is identified as a watershed moment when the object of perception becomes the object of discourse. Surveying Benjamin's definitions of aura, one becomes aware of two modes of perception, which are crucial for the understanding of atmospheres. The "atmospheric portfolio", therefore, provides for the possibility to explore the particular features of the phenomenon. It is a collection of studies and research methods, which, on the one hand, reflects on the terms and concepts, and, which, on the other, allows for exemplary experiments of the empirical approaches to the phenomenon.