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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
Pegasus M68 Male to M68 Male Adapter

Pegasus M68 Male to M68 Male Adapter

by Pegasus Astro
SKU PEG-ADAPT-M68M-M68M
$27.50 - $27.50
$27.50
$27.50 - $27.50
$27.50
Price Match Policy!
  • Adds 1.4 mm of back focus
  • M68 x 1.0mm male threads on both sides
  • 4 mm thread length for secure connection
  • Internal M54 x 0.75mm female thread
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Adapter M68 Male to M68 Male

    This M68 Male to M68 Male adapter provides a precise 1.4 mm of optical path length, ideal for fine-tuning back focus in critical imaging setups. Each side features an M68 male thread with a 1.0mm pitch and 4 mm of length for a secure fit between components. The adapter also includes a versatile inner M54 x 0.75mm female thread, allowing you to step down to smaller accessories without needing a separate adapter.

    Precision Spacing: A 1.4mm M68 Male-to-Male Adapter

    When your back focus calculation requires a small, precise adjustment, this adapter fills the gap. Its primary function is to join two female M68 threaded components, such as a focuser and a field flattener, while adding exactly 1.4 mm to the optical train. The M68 x 1.0mm threads are standard for many large-format correctors and focusers, making this a crucial part for achieving perfect star shapes to the edge of the frame.

    The adapter's utility is expanded by its internal M54 x 0.75mm female thread. This allows you to connect M54 accessories directly, offering a convenient step-down connection within your M68 imaging train. The thin but rigid design ensures no flexure, maintaining perfect optical alignment.

  • What is the primary use for this M68 Male to M68 Male adapter?

    This adapter is designed to connect two components that both have female M68 x 1.0mm threads, such as connecting a focuser drawtube directly to a field flattener or rotator. Its main purpose is to add a very specific 1.4 mm of spacing to achieve the correct back focus distance required by your optical system.

    How do I use the inner M54 thread on this M68 adapter?

    The inner M54 x 0.75mm female thread allows you to attach accessories with a male M54 thread directly to the adapter. This is useful for stepping down the connection size from M68 to M54 without needing an additional, thicker adapter, which helps conserve precious back focus.

    My imaging train is 1.5mm short of the correct back focus. Will this 1.4mm M68 adapter work?

    A 0.1mm difference is generally within the tolerance for most amateur imaging setups, especially with slower optical systems (f/7 or higher). While 1.5mm would be ideal, using this 1.4 mm adapter will likely produce excellent results and is far better than having a significant spacing error. For very fast systems (f/4 or below), that 0.1mm may have a minor impact on corner star shapes.

    What is the thread pitch of this M68 Male adapter?

    Both the external M68 male threads and the internal M54 female thread have a standard pitch for astronomical equipment. The M68 threads have a 1.0mm pitch, and the internal M54 thread has a 0.75mm pitch.

    Can I use this M68 adapter to connect my reducer to an off-axis guider?

    Yes, if both your reducer and off-axis guider present female M68 x 1.0mm threads and you need exactly 1.4 mm of additional spacing between them, this adapter is the perfect solution. It provides a rigid, threaded connection that maintains alignment.

    Is this M68 adapter suitable for a heavy, large-format camera?

    Absolutely. The 4 mm thread length on each side provides a secure, load-bearing connection that is more than adequate for large CCD or CMOS cameras. Threaded connections like this are significantly more rigid and resistant to tilt than compression or slip-fit adapters.

  • Adapter Thickness (Back Focus) 1.4 mm
    External Thread M68 Male (Pitch 1.0mm)
    Internal Thread M54 Female (Pitch 0.75mm)
    Thread Length 4 mm

    • Adapter M68 Male to M68 Male

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  • No downloads are available for this product.

  • This product is covered by a 1-year warranty against manufacturing defects.