GSO 8" F/12 M-LRS Classical Cassegrain Metal OTA (Black)

GSO 8" F/12 Metal Optical Tube Assembly: Reinventing the Classical Cassegrain Telescope

The Cassegrain telescope, once thought to be a relic of the past, has been revitalized by the innovative Taiwanese GSO factory. This resurgence is here to stay, as the Cassegrain design offers several unique advantages that have captured the attention of astronomers worldwide.

One of the standout features of the Cassegrain telescope is its superior cooling capability, outperforming both the Schmidt-Cassegrain and Maksutov-Cassegrain designs. This telescope operates solely on reflection, similar to RC and Newtonian telescopes, effectively eliminating any residual chromatic aberration caused by light deflection.

The Cassegrain telescope also boasts a longer focal length compared to typical RC or Newtonian telescopes, making it comparable to the Maksutov design. Despite its extended focal length, it remains compact, similar to RC and Mak telescopes.

A key characteristic of the Cassegrain system is its lack of a lens system, making it ideal for infrared photography. The long focal length simplifies the collimation process, a common challenge with RC telescopes, especially when used as exit telescopes.

The Cassegrain system features a primary mirror shaped as a rotational hyperboloid segment, paired with a secondary paraboloid mirror. Although manufacturing these surfaces is challenging, the GSO factory has successfully overcome these obstacles. The longer focal length and narrower field of view, typically seen as drawbacks, often prove beneficial by reducing distortions at the field edges and providing high-scale reproduction for photography and observations.

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

Technical Specifications:

• Design: Classic Cassegrain telescope
• Aperture: 8" / 203 mm
• Focal Length: 2436 mm
• Focal Ratio: f/12
• Resolving Power: 0.59"
• Visual Observing Limit: 13.6 magnitude
• Primary and Secondary Mirror Material: Quartz
• Mirror Reflectivity: 99% for each mirror
• Obstruction (linear, relative to diameter): 33%
• Focuser: 2" with 1.25" reduction and a 10:1 microfocus knob
• Includes: Two extension tubes (50 mm optical length each) with M90 threading
• Back Focus: 150 mm from the end of the 2" focuser drawtube
• Tube Diameter: 230 mm
• Finder Scope Mount: Vixen standard
• Dovetail: Vixen standard
• Length: Approximately 620 mm
• Weight: 7.5 kg
• Warranty: 24 months