The GSO 203/2436 Classic Cassegrain Binoculars Tube is the optimal choice for a high performance, yet highly portable, value for money binocular. The 203mm diameter optics collect 73.8% more light than the smaller 154mm model.
The long 2436 mm focus determines the instrument for achieving high magnifications for which it's easy to choose eyepieces with comfortable viewing angles, but it's also a good choice for not only visual but also astrophotography of planets, the Moon, the Sun and compact deep-sky objects, although its f12 aperture makes it a better fit for more sensitive astronomical cameras. As the optics are all mirror, chromatic aberration (colour aberration) cannot be caused by the optics. Its low 33% central occlusion promises a contrasting view, enhanced by well-designed shading blends.
The tubular mirror system of the GSO 203/2436 classic Cassegrain binoculars has a good light recovery, with the manufacturer claiming 99%. Because the telescope tube is open at the front, it can take in ambient temperatures much faster than closed-tube catadioptric instruments. Since the GSO 203/2436 classic Cassegrain telescope tube is fixed to the main mirror, there is no image-shift mirror tilting, which is a great relief when taking photographs. Parabolic main mirrors and hyperbolic auxiliary mirrors result in less coma failure and a more contrasty image than SC telescopes.
The telescope features a 2" dual-speed Crayford focusing eyepiece for accurate, jam-free focusing. The maximum field of view available is 1.15 degrees, which is approximately 1 full moon of sky. Accessories are not included.
