Takahashi FSQ-106EDX4 0.6x F/3 Reducer

Product Overview

The F/3 0.6x Reducer takes the FSQ-106EDX4's native focal length down to 320mm at f/3.0, one of the fastest focal ratios available for this astrograph. Four elements in three groups, fully multi-coated, deliver a Φ44mm image circle that Takahashi states covers a full 35mm sensor frame.

Who It's For

This reducer suits FSQ-106EDX4 owners chasing the fastest possible imaging speed — faint nebulosity, narrowband work under time pressure, or any target where cutting exposure time matters more than reach. At f/3.0 it gathers considerably more light per unit time than the FSQ-106EDX4's native configuration.

Key Features & Design

• 4 elements in 3 groups, multi-coated: built specifically to hold sharpness at an aggressive f/3.0.
• 0.6x reduction: takes the FSQ-106EDX4 to 320mm at f/3.0.
• Φ44mm image circle: covers a full 35mm frame per Takahashi's published figures.
• M72x1.0 mounting interface: threads directly into the FSQ-106EDX4's camera train.

Optical / Mechanical Design

Back focus is 56.2mm on the FSQ-106EDX4 with this reducer installed — the figure to build the rest of your imaging train around. See the Takahashi Back Focus Guide for the full spacing chain.

Recommended Uses

Fast narrowband and broadband imaging of faint nebulae and galaxies where exposure time is the limiting factor; wide-field deep-sky imaging where f/3.0 shortens total integration time significantly versus a native-focal-ratio setup.

Compatibility and Accessory Notes

Takahashi also lists this reducer against the FSQ-130ED, where it produces a 390mm focal length.

Good to Know Before You Order

Built for the FSQ-106EDX4 primarily: Takahashi also markets it against the FSQ-130ED.

Frequently Asked Questions

Is it difficult to set up?

No — it threads directly onto the FSQ-106EDX4's M72x1.0 interface, and the 56.2mm back focus figure is fixed once it's installed.

What is it best used for?

Fast deep-sky astrophotography on the FSQ-106EDX4, where f/3.0 cuts exposure time significantly on faint targets.

Does it work for visual observing?

No — it's built to deliver a flat photographic image circle rather than a visual eyepiece path.

What else do I need with it?

Your camera's own T-ring or adapter to complete the connection at the 56.2mm back focus figure.

Bottom Line

A fast 0.6x reducer that takes the FSQ-106EDX4 to 320mm at f/3.0 across a full-frame-covering Φ44mm image circle, at a 56.2mm back focus.