Reflector telescope aperture 76 mm focal length 300 mm focal ratio 139 optical systems reflector newton dobsonian suitable for beginners children max useful magnification 152 x tracking dobson mount dobson rockerbox tripod table top tripod telescope feature easily transportable astrophotography function none minimum useful magnification 10 coating fully coated eye piece 125 rack and pinion eyepiece focal length in mm 125 mm goto software