GTF 81 Five Element APO (Dovetail Plate Included)(Demo)

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The WO (William Optics) GTF 81 is a 5 element APO telescope designed for both visual and photographic use, and is an outstanding travel scope.

We recommend purchasing a WO 2” star diagonal and a 2“ photo adapter for best use of this telescope.

The GTF 81 is well suited to viewing nebulae, clusters, large galaxies and comets, so the use of high quality wide-angle eyepieces is highly recommended.

The WO SWAN, UWAN and SPL series eyepieces are available in a variety of focal lengths.

Viewing the moon and planets at magnifications of 180X is spectacular, when seeing conditions permit.

To calculate the magnification of your telescope and eyepiece combination, divide the telescope focal length in mm by the eyepiece focal length in mm.

Keep in mind that the atmosphere plays an important role in seeing conditions, and only the best seeing conditions will support high power viewing.

Additional power under less than ideal seeing conditions will not increase viewable details, and lower powered eyepieces should be used under those conditions.

It’s easiest to locate objects using low power eyepieces (20X magnification and lower) and then zoom in by switching to higher powered eyepieces.

The largest field of view can be seen by using a 12x low power-wide field of view eyepiece.

A stable tripod or mount is highly recommended for optimal viewing.

This includes high quality photography tripods, stable Alt-Atz mounts, and German Equatorial mounts, which are designed for astronomical use with the ability for precise tracking of celestial objects.

Optional accessories from WO include mounting rings and plates, and super high quality 2” Quartz star diagonals which provide for superior viewing and high quality images.

The GTF 81 telescope is perfect for large-field astrophotography.

The GTF 81 has superb color correction at a fast speed of f5.9.

More Information



Focal Ratio


Focal Length


Resolving Power


Limiting Magnitude


Objective Type

Five element with FPL-53 Air Spaced (2 groups), STM coatings.

Lens Shade



2" R&P 360° Rotating Camera-angle Adjuster, 1:10 fine focus Focuser Travel Length 3.15" (80mm) 1.25" Adapter

Field Stops

Knife-Edge Baffles

L-type Mount


Tube Diameter


Tube Length

(440 mm) Fully Retracted

(484 mm) Fully Extended

Tube Weight

8 lbs.( 3.7kg)

Optical Performance N/A
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