Takahashi Extender-Q 1.6X for FSQ-106 (Fluorite) and Sky-90

Product Overview

The Extender-Q is a five-element 1.6x tele-extender built for Takahashi's original fluorite FSQ-106 and Sky-90 Petzval refractors. Screwed into the focuser drawtube, it works as a 1.6x visual Barlow and as a photographic and CCD tele-extender, accepting standard 1.25-inch eyepieces and diagonals, with internal threading for filters and an optional upgrade path to 2-inch accessories.

Who It's For

This is a good match if you own the original fluorite FSQ-106 or a Sky-90 and want more focal length for lunar, planetary, or small-target imaging, or higher-power visual observing, from a telescope you already own.

Key Features & Design

• Five-element optical design: functions as both a 1.6x visual Barlow and a photographic tele-extender.
• 1.25-inch accessory compatibility: accepts standard eyepieces and diagonals, with an internal filter thread.
• 2-inch upgrade path: an optional adapter extends compatibility to 2-inch accessories.
• Direct drawtube mount: screws straight into the focuser, no separate adapter required on the FSQ-106 or Sky-90.

Optical / Mechanical Design

This extender serves the earlier fluorite FSQ-106 and the Sky-90 rather than the current FSQ-106EDX4. On the fluorite FSQ-106 it brings the focal ratio from f/5 to f/8; on the Sky-90, from f/5.56 to f/8.9. Takahashi publishes the resulting focal ratios for both pairings.

Recommended Uses

Higher-magnification lunar and planetary imaging and visual observing on an original fluorite FSQ-106 or Sky-90.

Compatibility and Accessory Notes

This is the extender for the original fluorite FSQ-106 and Sky-90 — both earlier Takahashi models. It is explicitly not compatible with the current FSQ-106EDX4 ("New Q"); that telescope uses the separate Extender-QE 1.6x, which Ontario Telescope also carries. If you are not sure which FSQ-106 generation you own, send us the tube's markings or serial plate and we will confirm the right extender. See the Takahashi Back Focus Guide for general spacing reference.

Good to Know Before You Order

Not for the FSQ-106EDX4: the current "New Q" telescope requires the Extender-QE 1.6x instead of this part.

Frequently Asked Questions

Is it difficult to set up?

No — it screws directly into the focuser drawtube on the FSQ-106 or Sky-90, with no separate adapter needed for the base 1.25-inch configuration.

What is it best used for?

Higher-power lunar, planetary, and visual work on the original fluorite FSQ-106 or Sky-90.

Will this fit my FSQ-106EDX4?

No — the FSQ-106EDX4 uses the Extender-QE 1.6x, a different part built for the New Q's 2-inch focuser and 44mm image circle.

Can I use it for imaging as well as visual?

Yes — Takahashi describes it as both a visual Barlow and a photographic tele-extender.

Bottom Line

The Extender-Q 1.6x is the matched tele-extender for the original fluorite FSQ-106 and Sky-90, bringing both to roughly f/8 for higher-power imaging and visual work, with an eyepiece-ready 1.25-inch interface and an optional path to 2-inch accessories.