Takahashi EX ED 1.5x Extender for FSQ-85EDX

Product Overview

The EX ED 1.5x is a 2-inch barrel extender built around extra-low-dispersion glass for the FSQ-85EDX, Takahashi's BabyQ Petzval astrograph. It brings the native 450mm f/5.3 up to 680mm f/8.0 while holding a 44mm corrected image circle, functioning as both a magnifying Barlow for visual use and a tele-extender for imaging.

Who It's For

This is a good match if you own the FSQ-85EDX and want tighter framing on smaller deep-sky targets — planetary nebulae, galaxies, globular clusters — than the astrograph's native wide field delivers, without losing the ED-corrected color performance.

Key Features & Design

• ED glass element: extra-low-dispersion glass controls chromatic aberration through the extended path.
• 1.5x magnification: 450mm f/5.3 becomes 680mm f/8.0 on the FSQ-85EDX.
• 44mm image circle held constant: the extended focal length stays corrected rather than trading correction for reach.
• 2-inch barrel interface: mounts directly to the FSQ-85EDX's 2-inch drawtube and doubles as a visual Barlow.

Optical / Mechanical Design

The FSQ-85EDX's four-element Petzval design is corrected natively at 450mm f/5.3 for wide-field framing. The EX ED 1.5x adds a low-dispersion element ahead of the focuser to extend the focal length to 680mm at f/8.0 while holding the 44mm image circle and 117.5mm back focus that the astrograph is designed around, rather than simply magnifying and letting the corners degrade.

Recommended Uses

Tighter deep-sky framing on the FSQ-85EDX — small galaxies, planetary nebulae, and globular clusters — and higher-magnification visual or lunar/planetary use when stacked with the TOA-35FL flattener on a TSA-120, TOA-130NS/NFB, or TOA-150B.

Compatibility and Accessory Notes

Takahashi publishes this extender on its own for the FSQ-85EDX, and stacked with the TOA-35FL flattener for three additional telescopes.

For the stacked configurations, the TOA-35FL flattener is a separate part Ontario Telescope also carries. Full spacing detail is in the Takahashi Back Focus Guide.

Good to Know Before You Order

Stacked use needs the TOA-35FL separately: the TSA-120/TOA-130/TOA-150B figures above require both parts together, not this extender alone.

Frequently Asked Questions

Is it difficult to set up?

No — it threads onto the FSQ-85EDX's 2-inch drawtube directly, with the 117.5mm back focus fixed by the unit.

What is it best used for?

Tighter deep-sky framing on the FSQ-85EDX, and longer-focal-length imaging on TOA/TSA triplets when paired with the TOA-35FL.

Does it work as a visual Barlow too?

Yes — the same 2-inch barrel design functions as a 1.5x magnifier for eyepiece use.

Can I use it on my TOA-130 without the TOA-35FL?

Takahashi's published figures for the TOA/TSA telescopes are for the extender stacked with the TOA-35FL flattener; send us your setup and we will confirm what the pairing does for your specific train.

Bottom Line

The EX ED 1.5x brings the FSQ-85EDX to 680mm at f/8.0 with its 44mm image circle intact, and extends further reach to the TSA-120 and TOA-130/150B line when stacked with the TOA-35FL flattener.