GTF 81mm 5 element APO

Product Code: A-F81GTA
Out Of Stock
Price: US$1,028US$1,200

Available Options

81 Soft Case (BG1-P002):


Gran Turismo (GT) 81 APO is an air-spaced Triplet FPL-53 Apochromatic with ED flattener refractor.

F/6.6 lens has a heart of super low dispersion glass that reduces any secondary spectrum to an unbelievable degree. This package includes guiding rings.

Aperture 81mm
Focal Ratio F/6.6
Focal Length 535mm
Resolving Power 1.43 second of arc
Limiting Magnitude 12.2
Objective Type Five element with FPL-53 Air Spaced (2 groups), Fully Multi-Coated, STM coatings
Lens Shade Retractable with locking screw
R&P Focuser

2" 360° Rotating Camera-angle Adjuster, 1:10 fine focus

Travel Length 3.15" (80 mm)

2" Brass Compression Ring

View Finder & Handle Illuminating V Shape-
1.25" Adapter Brass Compression Ring Included
Tube Diameter 90mm
Tube Length (440 mm) Fully Retracted

(484 mm) Fully Extended

Tube Weight 8 lbs.( 3.7kg)


Specification for Apochromatic Lenses

All WO refractors objective are double tested and inspected before shipping to our customer, these telescopes are free of coma and astigmatism.
Since all individual lens surfaces are machine coated sometime it could have visual imperfections which do not affect the objective optical performance.


Dimensions of scratches and points shall not exceed the following values:

Surface finish class Scratches Points Accumulation of defects Width,not more, mm Total length, not more, mm, Diameter no more,mm, Quantity, no more Diameter. 


Scratches Width, not more, mm 0.025mm
Total length, not more 1/4 of total lens diameter. 
Quantity no more 3
Dots or spot points No more, mm 0.4mm
Quantity, no more 3
Accumulation of defects Limited area, mm 0.8mm^2
Total area of scratches and points, no more, square mm 5.8mm^2


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