[66900]90FL F4 Astrograph Set Part # 66900 Description 90FL F4 Astrograph Set Aperture 90mm Fluorite Focal length 360mm F-ratio 4.0 Lens configuration 6 elements in 5 groups Coating Fully multi-coated Physical length 400mm Tube diameter 80mm Weight 1.9kg Filter 82mm (front cap) & 48mm in front of reducer Parts included 2591, 7151, 7801, 7835, 7872 & 7352 Notes