Takahashi EX CQ 1.7x Extender for FS-60CB (FS-60Q Conversion)

Product Overview

The EX CQ 1.7x Extender installs between the focuser and the FS-60CB's fluorite doublet objective, converting the tube's optics to the same 600 mm f/10.0 configuration published for the FS-60Q. It threads in place with an M55.9 mount and flattens the image circle to 44 mm at the same time as it extends the focal length.

Who It's For

This is a good match if you already own the FS-60CB and want the FS-60Q's longer reach — for solar eclipse photography, lunar and planetary imaging, and higher-magnification visual use — without buying a second optical tube.

Key Features & Design

• Converts FS-60CB to FS-60Q spec: 355mm f/5.9 becomes 600mm f/10.0, matching Takahashi's own FS-60Q optical tube.
• 44mm flattened image circle: the extended path is corrected at the same time it is lengthened.
• Installs between focuser and tube: a permanent-feeling but removable module rather than a drawtube accessory.
• Opens up reducer options: Takahashi notes the resulting f/10 system can be brought back down toward f/6.2 or f/4.2 with the matching reducers.

Optical / Mechanical Design

The FS-60 platform ships as a 355mm f/5.9 fluorite doublet in CB form. The EX CQ 1.7x sits ahead of the focuser and behind the objective, changing the light path so the whole system performs exactly as Takahashi's dedicated FS-60Q tube does — 600mm at f/10.0, with the image circle flattened to 44mm and a published back focus of 158.4mm from the rear of the module.

Recommended Uses

Solar eclipse and transit photography at longer focal length, lunar and planetary imaging, and higher-power visual observing on a compact 60mm platform.

Compatibility and Accessory Notes

Takahashi publishes this pairing for the FS-60CB specifically.

The resulting figures match Takahashi's own FS-60Q optical tube exactly, so accessories rated for the FS-60Q's back focus generally carry over. Full spacing guidance is in the Takahashi Back Focus Guide.

Good to Know Before You Order

It replaces the CB configuration rather than sitting alongside it: once installed, the tube runs at f/10.0 until the module is removed.

Frequently Asked Questions

Is it difficult to set up?

No — it installs as a single module between the focuser and the objective cell, with no separate spacing to calculate for the base configuration.

What is it best used for?

Extending the FS-60CB's reach for solar, lunar, and planetary work at f/10.0.

Does this make my FS-60CB an FS-60Q?

Optically, yes — the resulting focal length, ratio, image circle, and back focus match Takahashi's FS-60Q tube exactly.

Can I reduce the focal ratio back down afterward?

Takahashi notes the resulting f/10 system pairs with its own reducers to bring the ratio back toward f/6.2 or f/4.2 — send us your imaging setup and we will confirm the right one.

Bottom Line

The EX CQ 1.7x Extender turns an FS-60CB into the optical equivalent of Takahashi's FS-60Q — 600mm at f/10.0 with a 44mm flattened image circle and 158.4mm of back focus.