Takahashi FSQ-85EDX - 85 mm telescope tube only
FSQ-85EDX tube sold separately, with a 1.01× corrector and CAA rotating collar. The QB reducer replaces the corrector for a different photographic setup; check the connections.
CHF 3'299.00
QB0.73X Reducer for FSQ-85EDX: 44 mm corrected image circle, 72.2 mm mechanical back focus, four-element, two-group optical design.
CHF 543.28incl. Swiss VAT
Part Number TKA37580
Will be ordered for you
Delivery time: 5 to 7 business days
Estimated shipping: Between November 23 and 24, 2026
The Takahashi QB0.73X reducer, part number TKA37580, is designed for the FSQ-85EDX telescope. In this configuration, the manufacturer specifies a focal length of 330 mm and a focal ratio of f/3.9. This model should not be confused with the older QE0.73X: it is an updated version designed to improve correction for full-frame sensors.
The QB0.73X uses four elements in two groups, including one ED glass element. The specified corrected image circle is 44 mm. Field correction is a key consideration for astrophotography with a large sensor; the final result depends on the mount, the distance to the sensor, and the focus.
The reducer attaches to the telescope's rotating focusing collar. The manufacturer’s specifications list a male M72x1 input and a male M56x0.75 output. Its mechanical backfocus is 72.2 mm: this value applies to the reducer and should not be arbitrarily replaced with the standard distance of another accessory.
Takahashi describes how to use the CA-35 adapter for the SKY-90 at the output of the reducer to achieve a distance of 56.2 mm for a wide-field T-ring and a camera body. For a camera, check the connections and distances in the official FSQ-85EDX diagram. The telescope, camera, adapter, and T-ring are not listed as included with this model.
| Features | Value |
|---|---|
| Reference | TKA37580 |
| Corrected image circle | 44 mm |
| Mechanical Input Interface | M72x1 male thread |
| Mechanical Output Interface | M56x0.75 male thread |
| Mechanical backfocus | 72.2 mm |
| Dimensions | 78 mm x 63 mm |
| Weight | 520 g |
QB0.73X reducer only. The photographic adapters and the instrument must be purchased separately.
Here are a few accessories we've selected for this model, depending on your needs.
FSQ-85EDX tube sold separately, with a 1.01× corrector and CAA rotating collar. The QB reducer replaces the corrector for a different photographic setup; check the connections.
FSQ-85EDX with finder scope and mounting collar (sold separately), an alternative to the tube alone. Its 1.01× corrector is included; the QB is used in its place, without stacking.
CA-35 SKY90 TKA35201 ring, sold separately for the FSQ-85EDX photography kit with QB reducer. Check the camera adapter and focus according to the Takahashi diagram.
