Heliostar 76Ha Solar TelescopeDouble stack performance, single stack price 76mm aperture 630mm focal length f 8. 3 M42 t threads for camera attachment Official solar telescope of the Charlie Bates Solar Astronomy Project Integrated Heliostar solar finder, tube rings, and carry handle Integrated Triffid Tuner and Solis Etalon Technology <0. 5 bandpass H alpha fully multicoated lens Achromatic doublet design 2 inch dual speed Crayford focuser 11. 5mm, 1. 25 diagonal format blocking