1. Final Announcement: We're Saying Goodbye to AstronomyConnect. Read Our Closing Notice.
Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.

More Views

William Optics GTF81 81mm Apo Refractor with Built-In Flattener & DDG Focuser # A-F81GTA-DDG

4.8 (4 Reviews) Read Reviews Write Review
Brand William Optics
Part Number A-F81GTA-DDG
Availability available

Product Info

Manufacturer Description

The stunning new William Optics Gran Turismo GTF 81 Apo is the new jewel of the apochromatic refractor world. From the pristine white finish on the CNC tube to the elegant dark red trim, this beauty has more than just good looks. This new GTF81 features a 3-element objective using high-quality FPL-53 extra-low dispersion glass that reduces any secondary spectrum to an unbelievable degree. But what makes this scope truly unique is the second optical component - a 2-element built-in ED field flattener that corrects the field, providing an excellent flat field over a 40mm image circle.

Optically Unbeatable

  • Five element in two groups air-spaced objective (FPL-53) in adjustable CNC machined ultra high precision lens cell.
  • Extremely sharp.
  • Excellent color correction.
  • Each lens is Fully Multi-Coated with a special super-high transmission coating (STM Coating) on all surfaces.
  • This f/6.6 telescope is ideal for astrophotography.

2” R&P DDG Focuser

  • The Digital Display Gauge - DDG - allows you to take precise focusing readings down to two decimals precision instantly.
  • Extra-smooth 360 deg. rotatable 2" Rack & Pinion focuser with 1:10 dual speed: a treat to use during astrophotography. No image shifting!
  • Comes with two locking screws on angled positions for heavy load applications.
  • Large aluminum knob with installed thermometer and aluminum protection cover.

Finder / Guidescope Rings Included

  • Includes bracket that can accommodate finders with a tube diameter of up to 60-61mmm. Perfect for adding a finderscope or guiding scope.
  • Viewfinder/Guidescope shown in photos above is illustrative only and NOT included.

Simply Beautiful Finish

  • Pure William Optics quality fit and finish: powder-painted white CNC-machined aluminum tube, dark red trim finish, retractable dewshield, 360 deg. rotatable R&P focuser, dewshield cap, L-shaped Vixen-style mounting base.
  • Top quality anodizing.

Attention to Details

  • Includes 2" & 1.25" adapter.
  • Anti-marring brass compression rings.
  • Carry handle with V-shape night glowing illuminator.
  • 2-year warranty from WO.

Reviews

4.8 (Based on 4 Reviews) 100% of reviewers recommended this product.
Rating Distribution
Sort by
  • Date
  • Rating
  • Useful
    1. dsvanderbilt

      dsvanderbilt New Member

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by DSV of Rodeo, NM.
      1408147200
      Aug 15, 2014

      5.0 A Rolls-Royce scope at a Nissan price

      Pros:

      Accurate,Compact,Quality Lenses,Strong Construction

      Cons:

      Comments:

      Superb apochromatic objective lens with built-in field flattener. Excellent for astrophotography.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    2. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by MikeB of Thundersley, UK.
      1390694400
      Jan 25, 2014

      5.0 Great small refractor

      Pros:

      Compact,Precise Focusing,Easy to Use,Accurate Color,Quality Lenses

      Cons:

      Comments:

      The WO GTF-81 is a great refractor telescope for imaging. I selected this model as it is perfect for carry-on luggage weight and size. I was not disappointed and my first images were amazing.

      I opted for the non-DDG model and I think that should I have the opportunity to buy again I may have paid the extra for the DDG. That said the focusing is easy and accurate. I have added a motorised focuser to the scope as well as the WO 50mm right angle finder which I purchased at the same time.

      The only real criticisms I have about the scope are the length of travel required to focus my camera and eyepieces. Indeed eyepieces will not come into focus without the addition of a prism as there is not enough travel on the focusing tube. The other minor niggle is that with a camera attached there is not enough length to the dovetail to properly balance the scope on my mount.

      Both of those are minor issues and I would have no hesitation in recommending the telescope to anyone looking for this type of optically superior equipment.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    3. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Roger of Phoenix, Arizona.
      1386374400
      Dec 6, 2013

      5.0 Stunning quality

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Comments:

      Bought the GTF81 to serve as a finder scope on my 16" DOB. The quality of this little scope put a smile on my face the first time I held it in my hands. Still smiling every time I see stars like pinpoints from edge to edge, enjoying the fine focus knob too.
      Also, my experience with Agena's customer service was world class, amazing.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    4. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Dan of Gaithersburg, MD.
      1385769600
      Nov 29, 2013

      4.0 Very solid - some nice glass

      Pros:

      Quality Lenses,Accurate,Compact,Strong Construction

      Cons:

      Heavy

      Comments:

      I put "heavy" as a con, though to be honest if you've got a good astrophotography mount then this won't be an issue. William Optics scopes are built *strong*, so this is no featherweight with rolled steel/aluminum, but a machined, sturdy beast that if you drop on your foot will hurt your foot, the optics will be fine ;)

      The focuser is very solid, though I've had it out and found that with my CCD camera I've got it racked out quite a bit (a little over 7cm) and that seems to be a source of some flexure. With a DSLR this is probably not an issue. I have an OAG on the way which I think should rectify this.

      It would be nice if the finder rings had a quick disconnect feature, but you have to remove your finder/guide-scope from the rings in order to put the scope in its case. If the hex-screws were to the side a bit, this wouldn't be an issue...

      The dew-shield has a thumbscrew to hold it in place.

      I bolt the L-foot onto a Losmandy-style dovetail...

      Support from William Optics is excellent.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    Sort by
    • Date
    • Rating
    • Useful

      Specifications

      Telescope Aperture 3.19" (81mm)
      Manufacturer William Optics
      Telescope Aperture 81mm - 125mm
      Telescope Series William Optics GT