Optec 2" to 1¼” Compression Adapter

Starting Price: $85.00
Price as Configured: $85.00
Brand: Optec / SKU: OP-17663

The  Optec 2-inch to 1-1/4-inch Compression Adapter is the improved version of the #17662 1-1/4" adapter.  This new version features a solid brass compression ring with machined grooves to hold 1-1/4" eyepieces firmly without slippage.  A mere 1/8th turn of the upper locking ring tightens and loosens the 1-1/4" bore for easy use with gloved hands.

The #17663 offers a precision machined 2-inch outer diameter to fit into the drawtube of the TCF-S or TCF-Si focuser or any 2-inch focuser.  A dovetail cut matches the three thumbscrews on the TCF-S while the 1-1/4"  inner brass compression ring offers a non-marring alternative for 1-1/4" eyepieces and camera or instrument nosepieces.  The adapter is self-centering for any 1-1/4" eyepiece or instrument nosepiece.

The 2-inch tube features an industry standard M48x0.6mm female thread for 2-inch screw-in type filters.  Removing the lobed  locking ring (shown in red) and the brass compression ring leaves a snug-fitting T-adapter with male M42x0.75mm threads.

  • Overall Outside Diameter (locking ring):  2.20" (55.9mm)
  • Outside Diameter (main body):  1.995" (50.7mm)
  • Overall Height: 1.58" (40.2mm)
  • Clear Aperture: 1.25" (31.8mm)
  • Weight: 4.6 oz (130 g)
  • Back-focus Usage: 0.45" (11.5 mm)
Camera-side Compatibility:
  • TCF-S or TCF-Si focuser,
  • TCF-S3 or TCF-S3i focuser with #17804 3-inch to 2-inch reducer,
  • Any manufacturer's 2-inch focuser or receiver.
Price as Configured: $85.00

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Adapter drawing Download
Adapter drawing