WILLIAM OPTICS GT-81-WIFD Gran Turismo 81 WIFD Instruction Manual

: June 1, 2024
: WILLIAM OPTICS

Table of Contents

**** Warning
SPECIFICATION
PACKAGE CONTENT
PARTS
TELESCOPE DIAGRAM
OPERATION GUIDE
ACCESSORIES MAP
CUSTOMER SUPPORT
Read User Manual Online (PDF format)
Download This Manual (PDF format)

WILLIAM OPTICS GT-81-WIFD Gran Turismo 81 WIFD

**** Warning

Never aim your telescope or finder scope at the Sun without proper Solar filters installed on the front of the telescope. Doing so for even a moment may permanently damage your vision. Proper Solar filters consist of filters made by reputable manufacturers, designed to fit tightly over the front of the dew shield. Solar eyepiece filters are not considered safe, and should not be used. With proper front mounted Solar filters, the telescope will not be harmed by viewing the Sun.

SPECIFICATION

Focal Length : 478mm
Diameter: 81 mm
Aperture : f / 5. 9
M92 M92 M63
Focuser : WIFD (WO INTERNAL FOCUS DESIGN)
(Compatible with EAF)
Image Circle : >Full Frame (45mm)
Retracted Length : 421 mm
Extended Length : 5 0 2 mm
Dew Shield Circumference : 382mm
Dew Shield Diameter : , 121 mm
Weight : 7.89Ibs / 3.580kg (OTA only) 10.06Ibs / 4.565kg (OTA with ring, dovetail and saddle)

Spot Diagram

Longitudinal Aberration

NOTE:

We are using a new lens cell design that includes FP53 glass in the WO triplet series (GT and FLT series). This design is perfect for temperature compensation to better prevent pinched optics, that can occur in cold weather conditions.
Before storing your telescope, you must leave it uncovered, with the tube opened for enough time to allow it to adjust to the room temperature. You must make sure the telescope is completely dry of any dew or moisture before it can be safely stored.
The telescope should always be stored in a dry location, with a consistent temperature.

PACKAGE CONTENT

A. Dust Cover with Bahtinov Mask
B. Main Tube
C. 120mm Saddle Handle Bar
D. Camera Angle Rotation Device
E. M92 to M63 Adapter (for FLAT6AIII)
F. 210mm Vixen Style Dovetail Plate
G. Soft Carry Case
H. ZYGO Test Report

PARTS

A. Rear Dust Cap (M63)
B. 120mm Saddle Handle Bar
C. WIFD Focuser
D. Dew Shield Locking Screw
E. Dew Shield
F. Lens Cover with Bahtinov Mask
G. Front Bahtinov Mask Cover
H. M6 Screw Holes for Finder Bracket
I. Camera Angle Rotator
J. 210mm Dovetail
K. 2 Speed 10:1 Ratio Fine Knob
L. M4 Screw Holes for Finder Bracket
M. Locking Screws on Saddle Handle Bar (M4)
N. Camera Angle Rotation Locking Screw
0. Mounting Rings/ Knobs
P. Focuser Adjusting Knob with Thermometer
Q. M92 to M63 Adapter

TELESCOPE DIAGRAM

R & P GEAR SPACING SCREWS

Adjustment Screws (3 mm Allen Key) – Pull Screw
Adjustment Screws (2 mm Allen Key) – Push Screw
Can be Removed to Attach the Electronic Motorized
Device such as EAF (Please refer to the instructions on page 12)
Tension Screw (Please refer to Note 2)
Do Not Touch

IMPORTANT NOTE:

The focuser smoothness adjustment ONLY when necessary by progressively push & pull screws until you reach the desired smoothness.
When using the telescope with the motor, please ensure that the tension screw is not over-tightened. Over-tightening the tension screw may cause damage to the focuser.
Think of it like driving a car and pressing the gas pedal while also pressing the brake simultaneously. Just as this action could harm your car’s systems, over-tightening the tension screw could compromise the functionality of your telescope’s focuser.