GSO Cassegrain 6" F/12 150 mm classic Cassegrain OTA

The Cassegrain telescope, once considered extinct, is making a comeback thanks to the Taiwanese GSO factory. This construction offers a host of unique features, making it worth paying attention to.

One notable advantage of the Cassegrain telescope is its faster cooling time compared to Schmidt-Cassegrain and Maksutov-Cassegrain telescopes. It shares this characteristic with RC Newtonian telescopes. Another significant advantage is its complete absence of chromatic aberration. Unlike RC and Newtonian telescopes, the Cassegrain works solely on reflection and does not rely on light deflection.

The Cassegrain telescope also boasts a longer focal length, similar to the Maksutov telescope, while maintaining a compact design akin to RC and Mak telescopes. Its lack of a lens system makes it suitable for infrared photography, expanding its range of applications.

The extended focal length of the Cassegrain facilitates the collimation procedure, which can be a drawback for RC telescopes, especially when used as an exit telescope.

The Cassegrain system consists of a main mirror with the shape of a rotational and secondary paraboloids that form a slice of a rotational hyperboloid. While these surfaces have traditionally been challenging to manufacture, the GSO factory has successfully addressed this issue. The long focal length of the Cassegrain, which limits the field of view, actually proves advantageous by eliminating flaws at the edges of the field and providing high reproduction scale for both photography and observations.

The Cassegrain telescope is suitable for visual observations, planetary astrophotography, compact astrophotography with high-sensitivity cameras, and infrared photography.

Here are the technical parameters of the telescope:

• Construction: Classic Cassegrain telescope
• Active diameter: 6" / 154 mm
• Focal length: 1848 mm
• Aperture ratio: f/12
• Primary and secondary mirrors: Quartz
• Mirror reflectance: 99% for each mirror
• Obstruction (linear, relative to diameter): 33%
• Focuser: 2" with 1.25" reduction and a 10:1 microfocus knob
• Two extension tubes included (M90 thread, 50 mm optical length each)
• Tube diameter: 190 mm
• Finder foot: Yes, in Vixen standard
• Dovetail: Yes, in Vixen standard
• Length: 500 mm
• Weight: 5.5 kg

The Cassegrain telescope comes with a 24-month warranty, ensuring peace of mind for its users.