The EDQ series scopes are designed with imaging in mind. The quad-element optical system builds field correction right into the telescope — no separate flattener needed. Stars are round from center to corners straight out of the focuser, across sensors up to full frame. That's what makes the EDQ line different from conventional doublets and triplets, and it's what makes this reducer different from every other 0.8× reducer we sell.
The ATEDQR doesn't need to flatten the field — the scope already does that. Its only job is to speed the system up. It takes the EDQ's native f/7 and brings it down to f/5.6 — a 56% increase in light-gathering speed per pixel — while preserving the flat, corrected field the scope was designed to deliver. Shorter exposures, more signal per frame, wider field of view, and the same sharp, round stars from center to edge that you bought the EDQ for in the first place.
One Reducer, Three Scopes
The ATEDQR is optically designed to work with all three EDQ refractors:
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AT86EDQ: 602mm f/7 → 482mm f/5.6
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AT106EDQ: 742mm f/7 → 594mm f/5.6
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AT126EDQ: 882mm f/7 → 706mm f/5.6
All three scopes share the same back-end thread geometry, so one reducer works across the entire EDQ line. If you own more than one EDQ scope, you only need one reducer.
Full-Frame Coverage
This is where the ATEDQR differs from the dedicated reducers we sell for the AT80ED and AT102ED. Those reducers are designed for APS-C sensors and smaller — the image circle doesn't cover a full-frame chip. The ATEDQR covers full frame. Because the EDQ's built-in flattener already corrects the field across a large image circle, the reducer maintains that correction at the faster focal ratio. Stars stay round all the way to the corners of a full-frame DSLR or a large-format CMOS camera like the ASI2600MC.
Connection and Installation
The reducer threads directly onto the EDQ scope after you remove the visual adapter from the focuser back end. You then attach part of the photographic extension tube that ships with the scope — the upper section threads onto the reducer and provides the 48mm T-thread connection for your camera. The product manual (included, and available as a PDF download on this page) walks through the steps with photos.
Back focus is 55mm from the reducer's shoulder to the sensor. Most DSLR setups with a standard T-ring hit this spacing naturally. Dedicated CMOS astronomy cameras may need spacer rings to fine-tune — and it's worth getting right. The flat field the EDQ delivers is only as good as your spacing. Off by a few millimeters and the corners show it.
Features
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0.8× optical reduction for all three EDQ scopes. Works with the AT86EDQ, AT106EDQ, and AT126EDQ. Reduces f/7 to f/5.6 — 56% more light per pixel, shorter exposures, wider field of view.
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Full-frame sensor coverage. The EDQ's built-in field correction means the reducer maintains flat, corrected fields across full-frame chips — not just APS-C. Stars are round from center to corners on sensors up to 36×24mm.
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Preserves the EDQ's flat field. The quad-element optical design already corrects field curvature. The reducer speeds the system up without compromising the flat field you paid for.
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48mm T-thread camera connection. DSLR and mirrorless bodies connect via a T-ring (sold separately); dedicated CMOS/CCD astronomy cameras attach directly — 48mm T-threads are standard on most.
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55mm back focus. From the reducer shoulder to the sensor. Standard DSLR T-ring spacing typically hits this naturally. Dedicated cameras may need spacing adjustment with M48 spacer rings.
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Threaded scope-side connection. Threads onto the EDQ focuser back end after removing the visual adapter. Secure, repeatable positioning with no play or tilt.
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Fully multi-coated optics. Maximizes light transmission and minimizes internal reflections for cleaner, higher-contrast images.
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Lightweight at 8 oz. Minimal impact on balance — won't shift your imaging train's center of gravity significantly.
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Protective covers included. Slip-on rubber covers for both the 48mm T-thread end and the scope-side barrel.
Observing Tip
If you're shooting with the AT86EDQ at f/5.6, the wider field of view opens up targets that were hard to frame at f/7 — the Veil Nebula complex, the North America and Pelican pair, or M31 with its companion galaxies. The shorter focal length also means shorter exposures, which is forgiving on mounts that aren't perfectly guided. If your mount tracks well at 120-second subs at f/7, it'll track well at 90-second subs at f/5.6 — and you'll get more signal per frame.
Frequently Asked Questions
Will this work with non-EDQ Astro-Tech scopes?
No. The ATEDQR is designed specifically for the EDQ series and threads onto the EDQ focuser back end. It will not fit the AT80ED, AT102ED, AT115EDT, AT130EDT, or any other AT scope. Those scopes have their own dedicated reducers and flatteners.
Does this replace the field flattener in the EDQ?
No — the EDQ's built-in field flattener remains in the optical path. The reducer works in addition to it, not instead of it. The built-in flattener handles field correction; the reducer handles focal reduction. Together they deliver a flat, fast f/5.6 system.
How do I attach this to the scope?
Remove the visual adapter from the focuser back end. Thread the reducer onto the exposed threads. Then attach the upper section of the photographic extension tube (included with the scope) to the reducer. This provides the 48mm T-thread connection for your camera. The included product manual has step-by-step photos. If you have questions, call us — we've walked customers through this before.
Does this cover a full-frame sensor?
Yes. Unlike the AT80EDRF and AT102EDRF (which are APS-C only), the ATEDQR covers full-frame sensors. The EDQ's built-in field correction provides a large enough corrected image circle to maintain sharp stars across a 36×24mm chip at f/5.6.
What cameras work well with this?
Any camera that connects via 48mm T-threads — full-frame DSLRs (Canon EOS, Nikon FX, Sony full frame), APS-C DSLRs, and dedicated CMOS/CCD astronomy cameras. The ZWO ASI2600MC, ASI533MC, ASI294MC, and similar cameras are all excellent matches. DSLR and mirrorless bodies require a T-ring for your specific mount (sold separately).
How critical is the 55mm back focus?
Very. If the spacing from the reducer's shoulder to your sensor is off by more than a couple of millimeters, you'll see elongated stars toward the edges — even with the EDQ's flat field. M48 spacer rings in 1mm, 2mm, and 5mm increments let you dial it in. Measure once, mark your configuration, and it stays consistent.
Final Thoughts
The EDQ scopes are already flat-field imaging refractors. The ATEDQR makes them faster ones. It drops every scope in the series from f/7 to f/5.6, opens up the field of view, and cuts your exposure times — while preserving the flat, corrected field that makes the EDQ design worth owning. If you're imaging with an AT86EDQ, AT106EDQ, or AT126EDQ and you want to work faster without sacrificing what makes these scopes special, this is the reducer that was designed for the job.
