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AP 2.7-inch Telescope Adapters

 

Astro-Physics 2.7-inch Threaded Extension Rings

Telescope Adapters and Extensions for the AstroPhysics 2.7 thread
Extensions, Adapters and Retaining Rings

#17824 - Meade RCX to OPTEC-3600 MountThe ubiquitous AP2.7 inch thread has become an astronomy industry standard thanks to the tireless efforts of Roland and his team at Astro-Physics.   Optec has produced an extension set and a few new adapters in an effort to extend this industry standard. 

Optec's AP 2.7-inch extension tubes feature female threads on one end with male threads on the opposite endAP 2.7 Extension Tubes with knurled bases to help attach and detach these tubes.  The extensions can be combined and stacked. We believe our four and five piece sets will provide all the needed extension for fixed focal length telescopes with 1/4" (12.7mm) increments using a minimum number of pieces.  Click here for a table of the optimized spacer combinations. 

All extensions and mounts are made from high strength 6061 aluminum alloy and black anodized.  Anti-reflection threading and internal baffles on the largest extension tube help minimize internal reflections.  All internal surfaces are painted and baked with a non-reflecting ultra-flat black paint. 

  • Spacer Lengths Available: 1/2", 3/4", 1", 1-1/2", and 3"
  • Clear Aperture: 2.52" (64mm)
  • Back-focus Usage: Variable (see TABLE)
Extension Tube Sets

Stock #19880
AP2.7 Extension Tube Set, 4-piece set
  • Includes: 1/2", 3/4", 1", and 1-1/2"
  • Possible spacer combinations:
    0.5" through 3.25" with 1/4-inch increments plus 3.75" with all spacers combined.  (See Table for combinations.)

AP2.7-inch Extension Ring 

Stock #19881
AP2.7 Extension Tube Set, 5-piece set
  • Includes:  1/2", 3/4", 1", 1-1/2", and 3"
  • Possible spacer combinations: 
    0.5" through 6.25" with 1/4-inch increments plus 6.75" with all spacers combined.  (See Table for combinations.)

AP2.7-inch Extension Ring

 
 Individual Extension Tubes and Retainers
Stock #19882
AP2.7 Extension - 1/2" Length
  • Overall Height: 0.88"  (22.4mm)
  • Clear Aperture: 2.52" (64mm)
  • Weight: 1.0 oz (30 g)
  • Back-focus Usage: 0.50" (12.7mm)

AP2.7-inch Extension Ring 

Stock #19883
AP2.7 Extension - 3/4" Length
  • Overall Height: 1.13" (28.7mm)
  • Clear Aperture: 2.52" (64mm)
  • Weight: 1.4 oz (40 g)
  • Back-focus Usage: 0.75" (19.1mm)

AP2.7-inch Extension Ring

 
Stock #19884
AP2.7 Extension - 1" Length
  • Overall Height: 1.38" (35.0mm)
  • Clear Aperture: 2.52" (64mm)
  • Weight: 1.8 oz (55 g)
  • Back-focus Usage: 1.00" (25.4mm)

AP2.7-inch Extension Ring

 
Stock #19885
AP2.7 Extension - 1-1/2" Length
  • Overall Height: 1.87"  (47.5mm)
  • Clear Aperture: 2.52" (64mm)
  • Weight: 2.4 oz (70 g)
  • Back-focus Usage: 1.50" (38.1mm)

AP2.7-inch Extension Ring

 
Stock #19886
AP2.7 Extension - 3" Length
  • Overall Height: 3.38" (85.8mm)
  • Clear Aperture: 2.52" (64mm)
  • Weight: 8.2 oz (230 g)
  • Back-focus Usage: 3.00" (76.2mm)

AP2.7-inch Extension Ring

 
Stock #19888
AP2.7 Retaining Ring
  • Overall Height: 0.10" (2.5mm)
  • Outside Diameter: 3.5" (88.9mm)
  • Clear Aperture: 2.69" (68 mm)
  • Weight: 0.6 oz (15 g)
  • Anodize:  Gold

AP2.7-inch Retaining Ring

 
Additional Product Views:

AP 2.7 Spacers with Retainer   AP 2.7 Spacers with Retainer

Click to see how the retaining ring can set spacing resolutions of 1.00mm or less.