Astro-Tech AT60ED Field Flattener


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This thread on field flattener for the AT60ED is a must for full frame photography.
Our Product #: AT60FF
Astro-Tech Product #: AT60FF
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Product Description

The Astro-Tech 60ED 1x flattener easily threads on to the focuser of your AT60ED after your remove the standard compression ring eyepiece holder. The flattener produces wonderful flat fields as well as a 41mm image circle. The threads on the t-ring side of the flattener are 48mm male. Make sure your t-ring will work with this particular flattener. The standard for years has been 42mm and not 48mm, so please double check your equipment. Backfocus from the rear shoulder of the AT60FF to the image plane is 54.8mm, so you may require some additional spacers to reach focus.

Tech Details


Review by:
I can't believe how well the AT60FF works with my AT60ED and at half the price of similar flatteners! This piece easily integrates with the AT60CAA and a standard 48mm T-ring. If you're planning on using this with a Nikon D5600 or other SLR with similar FFD, you should be able to reach a proper back focus with just the standard T-ring. No fiddling with spacers is required which is an added plus. (Posted on 10/23/2019)
Review by:
I use this along with the CAA with my WO ZS61 and my Nikon Z6 or D5600. I’m not a pixel-peeper, but the stars generally look good even to the edge of the full frame sensor. I’ve never worried about spacers - I just connect either camera to this using a standard 48mm adapter (and an F to Z adapter for the Z6), this screws onto the CAA, and that screws onto the scope. Solid connections all the way. (Posted on 8/18/2019)
Review by:
Received this with the 60ED and first test images with a standard Canon SL1 showed round stars to field edge. No issues with back focal length after adding a 10mm spacer. Great purchase experience and service from Astronomics. (Posted on 7/24/2019)
Review by:
The flattener for the AT60ED gives nice stars even in the corners of my DSLR. This combo produces some really nice wide field images. I have a long list of targets for this little guy. (Posted on 7/22/2019)
Review by:
I purchased the flattener from Astronomics for use with the William Optics ZS61 scope. This flattener is identical to the original (non-adjustable) WO flattener, but at a significantly discounted price. It works perfectly on the WO telescope -- round stars out to the edge of my APS-C Canon T3i field, great results with the ZWO ASI183MM-Pro camera. Quality construction, no optical tilt, and no apparent chromatic aberration. A great product at a great price! Just be sure to get the 55mm spacing to the imaging chip correct. (Posted on 7/22/2019)
Review by:
Nice flattener gives pinpoint stars in the corners of my DSLR images as well as my 4/3 astro cameras. (Posted on 11/15/2018)
Review by:
I got this to image with my AT60ED, and I would say it's a must-have addition for larger-chip imaging. I'm using an APS-C sized chip (Fuji X-A1). This flattens the field very nicely out to the corners, without any noticeable vignetting or other adverse effects on image quality. There's part of me that wishes this scope had a built-in flattener, as field curvature is very obvious with a wide angle low-power 2" eyepiece. But this would probably get in the way of some visual uses and lead to collimation headaches. And I hate to think what it would cost to solve such problems! This accessory works just fine and preserves the versatility and economy of the AT60ED. (FWIW, my solution for low-power visual use is to just use a different low power 2" eyepiece, namely the 30mm TMB Paragon instead of the 38mm SWA, to provide a smaller but sharper field of view.) (Posted on 11/6/2018)
Review by:
This is a good quality field flattener that is easily adaptable by putting on different spacer/adapters of the same length. It is a necessary accessory if you plan to use the AT60ED photographically. Luckily, it is available at a great price! (Posted on 10/6/2018)
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