In astronomical terms, the field of view is the area of the sky imaged by a sensor. The sensor could be your eye or a camera CCD, etc. My regular camera has a CCD with 2184 x 1472 pixels. The optics provide an image of 1.04″(seconds of arc) per pixel. So, the image’s field of view is 37.85′(minutes of arc) by 25.5′. To put that into perspective, the width of the Moon is about 30.0′. So the full Moon would fit in my FOV side to side but be cut-off at the top and bottom.