Takahashi 645RD QE0.72x Focal Reducer

for FSQ-106EDX4

• Medium format, fully covered. The 645RD QE0.72x brings a 60 mm corrected image circle to the FSQ-106EDX4, opening the door to true medium-format imaging on an already acclaimed astrograph.
• Faster and wider in one step. Four large-diameter lenses across four groups bring the focal length down to 380 mm at F/3.6, so the FSQ-106EDX4 now covers two perfectly corrected focal lengths: 530 mm (F/5) native and 380 mm (F/3.6) reduced.
• Edge-to-edge light, not just center punch. Off-axis illumination is over 70% at the periphery of the field and over 90% across the 44 mm full-frame diagonal, roughly 50% more than the previous QE0.73x reducer, so vignetting is nearly imperceptible on today's cooled CCD and DSLR cameras.
• Violet fringing, addressed. The slight violet chromatic aberration near 420 nm seen on the QE0.73x is almost completely corrected here, with the diffraction spot cut to about two-thirds of its previous size across the 44 mm image circle.
• Coated for cleaner light. A broad-spectrum multilayer coating cuts reflections to less than half that of a conventional coating centered near 500 nm, reducing ghost images and boosting transmission across the full visible spectrum.
• Mounted where it counts. Instead of screwing to the focuser like a typical reducer, the 645RD screws directly to the rear of the G4 lens inside the optical tube, taking the load off the eyepiece holder rather than piling it on.
• Framing flexibility on the classic ED version. On the classic ED model, the Camera Angle Adjuster (TKP86200, sold separately) can swap in for the TKA36582 extension ring to make framing easier.

Specifications

• Optical Design: 4 lenses (4 groups)
• Corrected Image Circle: 60 mm
• Input Mechanical Interface: M72x0.75 thread, male
• Output Mechanical Interface: None
• Metal Back Distance: 56.2 mm
• Total Length: 74.2 mm
• Weight: 200 g
• Compatibility: Takahashi FSQ-106EDX4 refractor

What's in the Box?

• 645RD QE0.72x Focal Reducer x1

Note: The reducer mounts internally to the rear of the G4 lens rather than to the focuser. The Camera Angle Adjuster (TKP86200) for the classic ED version is sold separately.