Refractor telescope aperture 127 mm focal length 635 mm focal ratio 15 optical systems fraunhofer achromatic refractor suitable for enthusiasts max useful magnification 254 x tracking equatorial mount equatorial mount exos 1 tripod steel tripod features dew shield telescope features astrophotography suitable barlow lens compatible astrophotography function possible with tripod piggyback setup minimum useful magnification 18 coating fully coated s