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 without ota mount without ota tripod not included telescope feature astrophotography suitable astrophotography function digiscoping minimum useful magnification 18 series bresser messier resolution power 091 bogensekunden light collecting power 7mm pupil 330