Astronomy binoculars area of use astronomy magnification 20 x lens diameter 80 mm prism system porro exit pupil diameter 4 mm min focus distance 244 m angle of view 32 field of view in 1000 m 56 m twilight factor 40 relative brightness 16 focussing system central focus viewing binocular weight 2 665 g included in delivery pouch tripod adapter outdoor function waterproof prismenglas bak 4