The Skywatcher ED100 0.85x focal reducer lens is a premium optical accessory specifically designed for Sky-Watcher Pro 100 ED and EvoStar 100 ED APO telescopes.

Its main advantage is its ability to reduce the telescope's focal length by 0.85x. This means it offers a wider field of view and a decreased focal ratio of approximately f/7.65, enhancing astrophotographers' ability to capture large sections of the sky with significantly shorter exposure times.

Additionally, the focal reducer also functions as a field flattener, which is crucial for correcting distortion and edge aberrations in the image. Without this correction, stars near the periphery may appear distorted, thereby limiting image quality.

Main features and technical specifications:

• Focal Reduction Factor: 0.85x, allowing faster focal ratios.
• Compatible Telescope: Designed for Sky-Watcher Pro 100 ED / EvoStar 100 ED APO telescopes.
• Optical Design: Combines focal reduction with field flattening for better image quality.
• Back Focus Distance: 55 mm from the start of the M48 threading to the camera flange.
• Thread Mount: Male M48 x 0.75 thread; requires M48 T-ring adapter.
• Weight: Approximately 0.7 lbs (300 grams).
• Coatings: Multi-coated optics for optimized light transmission.

Overall, the Skywatcher ED100 focal reducer is an essential tool for astrophotographers seeking to enhance their imaging capabilities while effectively utilizing their telescope.