iOptron Photron 355mm f/8 Ritchey-Chretien Catadioptric Truss-Tube Telescope (OTA Only)

The iOptron Photron 355mm f/8 Ritchey-Chretien Catadioptric Truss-Tube Telescope builds on the success of the solid tube models in the series with a completely redesigned housing that utilizes an open truss system to improve the overall thermal dynamics that allow the optical system to settle into the ambient temperature faster and resist heating up better than traditional closed steel tubes. Carbon fiber tubes used in the trusses are also thermally stable so they won't expand and contract like metal does, ensuring accurate alignment throughout the night and throughout the year. This new optical tube design enables larger apertures than closed steel tubes, making this model one of the largest in the Photron family of scopes. Intended for those who have a solid and reliable support system, iOptron is offering the RCT here as an (optical tube assembly) OTA-only option. A long Losmandy-style dovetail plate is factory installed to make it compatible with a wide variety of heavy-duty mounts and piers that can carry a minimum payload of at least 66 pounds.

As with all Photrons, the Ritchey-Chretien (RCT) optical system utilizes the same hyperbolic primary and secondary mirror design used in the Hubble Space Telescope, the Keck telescopes, and the ESO Very Large Telescope to deliver the wide field of view and superb performance advanced amateur astronomers and imagers demand. Complementing the improved heat management of the open truss system are low thermal-expansion quartz primary and secondary mirrors and three cooling fans that further help keep the optical system cool during long observation sessions. Each mirror is treated with highly reflective dielectric coatings that maximize the light being transmitted, so greater than 99% of the available light makes it to your eye or imaging sensor. All of this translates to bright and sharp high-contrast views or images with accurate color fidelity across the entire wide distortion-free field of view. The 14" aperture has the light-gathering capability required to see dim deep-space objects like galaxies with a respectable f/8 focal ratio that is ideal for long-exposure astrophotography techniques.

Unlike other catadioptric designs, this RCT has a fixed primary mirror to eliminate the image shift that is common with conventional configurations that move the mirror forward and back to focus the image. With the primary mirror fixed in place, iOptron opted for a precise two-speed Crayford-style focuser with a 10:1 reducer that allows for fast coarse and precise fine focusing without the backlash that occurs in the more common rack-and-pinion design�essential for astrophotography or splitting binary stars. To ensure complete coverage of today's imaging sensors, the focuser has a large 3" drawtube and comes with three extension rings to help users achieve the proper back focus distance. The larger drawtube also allows the use of large 2" eyepieces, which generally have longer eye reliefs to make visual observations much more comfortable, and comes with a 1.25" reducer to enable the smaller and more common-sized eyepieces and accessories to be easily used.

iOptron Photron Specs