Refractor telescope aperture 60 mm focal length 700 mm focal ratio 1117 optical system refractor suitable for beginners children max useful magnification 142 x tracking altazimuth mount altazimuth tripod aluminium tripod telescope features astrophotography suitable barlow lens compatible easily transportable astrophotography function possible with tripod piggyback setup minimum useful magnification 8 coating fully coated series celestron powerseeke