William Optics Flattener 4 - AFR-IV
The revolutionary William Optics AFR-IV Adjustable Flattener and (0.75x-0.8x) reducer is made for 500-1000mm refractors, including the William Optics FLT98, FLT110, FLT132, and others. This 2-element, 2" is black-anodized for durability and beauty. All internal surfaces are blackened to eliminate reflections.
The WO AFR-IV Flattener has a rotating t-ring thread that will accept any standard t-ring for your camera. The included T-ring adapter comes with a locking screw and extra retaining screws. This field flattener inserts directly into a 2" focuser. It is easy to set the optimum back focus distance...just twist.
William Optics AFR-IV Flattener Highlights...
- The lens is designed to cover full size DSLR cameras with a clear lens aperture of 54 mm
- The WO Flattener 4 has an excellent air-spaced doublet design with STM coatings, and is made with the best Ohara optical glass.
- Superb William Optics anodized finish.
- All internal surfaces are threaded and blackened.
- Rotating T-ring thread for any 35mm camera. The T-ring adapter is provided with a lock screw and extra lock retaining screws.
- Will accept any standard T-ring for your camera.
- Inserts directly into 2" focuser.
- Lens-to-chip distance : 66-86mm
- 0.75x-0.8x Reducer
- Rotating T-ring adapter
- Clear Aperture : 54mm
- L 84mm : W 95mm : H 144mm
- Weight : 595 g
- Additional Information
SKU WO-P-FLAT4 Manufacturer William Optics Barrel Size 2" Warranty 2 Year Warranty
Customer Reviews 1 item(s)
- The Quality Standard of Service
The FLAT-4 focal reducer did not work on my ES102 apo. However, Chris Hendren, the OPT imaging specialist, gave me a thorough clinic on how reducers work with just enough technical information so that I could understand. He had suggestions which I tried but ultimately it was just an equipment mismatch. I had worked with the product for more than 30 days so knew my right to a refund was forfeit. OPT gave me an RMA for store merchandise minus a 10% restocking charge . When I sent it back, though, the full purchase price showed up as a refund on my credit card. This is a great company that will go to those lengths for their customers. I would recommend OPT without reservation, and look forward to more purchases in the future.
1= Houston, We Have a Problem & 5= It's Out of This World
- Included Items
- William Optics Flattener 4 - AFR-IV
- Rotating T-Ring Adapter
- Questions & Answers
Product QuestionsI have a William Optics FLT 110, wich flattener is better for it? This one or the WO flattener 68II? Another question, the thread for the T-ring is m42 or m48 in the flattener 4? Thank you.Question by: Eduardo Schaberger on Apr 27, 2016 10:00:00 PMDepending on which focuser you have on your FLT110, both could work quite well, but this is guaranteed to fit due to the 2" nosepiece on the scope side. The side facing the camera is a standard M42 T-ring, while the Flat68II uses an M48 Wide-T connection.Answer by: Chris Hendren (Admin) on Apr 29, 2016 4:55:00 PMDo you know if this will work on an Astro-Physics 130 GT with a focal length of 819mm?
I am imaging with a Canon 60Da DSLR.
WilliamQuestion by: William Rison on Jul 18, 2015 4:09:00 AMThere is a possibility that this will work, as it will work on a WO 132mm f/7 scope, but without testing it there would be now way to tell for sure how large the corrected field would be. The faster A-P scope will likely need additiona longer flattener-to-camera spacing due to the stronger field curvature at f/6.3, but without your scope and camera and a few T-thread spacers, we could not predict the exact spacing.Answer by: Chris Hendren on Jul 24, 2015 4:01:00 PMWill this work with Orion EON 120mm (900mm focal length with 7.5 focal ratio) and QSI583 WSG CCD?Question by: Jasem Mutlaq on Jan 9, 2017 10:10:00 PMThis will probably work, although the 0.85x reducer that Orion and Sky-Watcher sell will likely offer better performance with a larger sensor. Back focus may be an issue, so use a short T2 spacer (5-7mm is ideal) to allow the camera to connect and see how the corners look with the reducer adjusted to near the minimum spacing (around the 66mm mark). If you are not happy with the corners, make slight adjustments outward on the reducer spacing and re-focus to check the corner correction until you find a position that works. You may never get the guide CCD to look perfect, so concentrate just on finding the best spacing for the main CCD.Answer by: Chris Hendren (Admin) on Jan 10, 2017 8:54:00 AMI have a TS120 mm 900mm f7.5 telescope and a Televue TV-76 I use with an Atik infinity camera. My question is how does one calculate the adjustable focus distance the flattener 4 should be adjusted to? Is there a formula to use? I think the Atik Infinity has a 13mm distance from chip sensor to coupling ring.Question by: Steve on Oct 15, 2016 4:11:00 PMThe distance gets shorter the longer the scope's focal length gets. Here are recommended distances the manufacturer provides:
FLT 98 - 76.8 mm (617mm FL)
FLT 110 - 73.5 mm (770mm FL)
FLT 132 - 71.5 mm (925mm FL)
GT 102 - 76 mm (703mm FL)
M90 - 77.3mm (620mm FL)
For a 900mm FL scope, try around 72mm spacing. For the TV-76, it will be somewhat longer than 80mm.Answer by: Chris Hendren (Admin) on Oct 30, 2016 3:22:00 PM
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