Refractor telescope aperture 127 mm focal length 635 mm focal ratio 15 optical systems fraunhofer achromatic refractor suitable for enthusiasts experts max useful magnification 254 x tracking equatorial mount equatorial mount exos 2 tripod steel tripod telescope feature astrophotography suitable astrophotography function digiscoping minimum useful magnification 18 series bresser messier resolution power 091 bogensekunden light collecting power