[69901]90FL F4 Astrograph Set (M75 Helical Focuser) Part # 69901 Description 90FL F4 Astrograph Set (M75 Helical Focuser) Aperture 90mm Fluorite Focal length 360mm F-ratio 4.0 Lens configuration 6 elements in 5 groups Coating Fully multi-coated Physical length 385mm Tube diameter 80mm Weight 2.1 kg Filter 82mm (front cap) & 48mm in front of reducer Parts included 2591, 7875, 7051, 7026, 7801, 7507, 7352, 7872 & 7000 Notes