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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.
Explore Scientific Extension Ring Set M48x0.75 - 5 pieces (30, 20, 15, 10 and 5 mm) - Discontinued
Explore Scientific Extension Ring Set M48x0.75 - 5 pieces (30, 20, 15, 10 and 5 mm) - Discontinued
Explore Scientific Extension Ring Set M48x0.75 - 5 pieces (30, 20, 15, 10 and 5 mm) - Discontinued

Explore Scientific Extension Ring Set M48x0.75 - 5 pieces (30, 20, 15, 10 and 5 mm) - Discontinued

by Explore Scientific
SKU ES-510381
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$69.99 - $69.99
$69.99
$69.99 - $69.99
$69.99
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  • Set of 5 extension tubes: 5, 10, 15, 20, and 30 mm
  • Standard M48x0.75 female and male threads on each tube
  • Provides combined extension from 5 mm to 80 mm
  • Wide internal bore minimizes vignetting with large sensors
  • Matte black anodized aluminum construction reduces internal reflections
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Explore Scientific Extension Ring Set M48x0.75 - 5 pieces (30, 20, 15, 10 and 5 mm)

    The Explore Scientific M48 Extension Ring Set includes 5 individual tubes with standard M48x0.75 threads, providing lengths of 5, 10, 15, 20, and 30 mm. This kit is the definitive solution for achieving the precise back focus required by field flatteners, reducers, and off-axis guiders. By combining the 5 included rings, you can create any extension length from 5 mm up to a total of 80 mm in 5 mm increments, ensuring perfect sensor-to-corrector spacing.

    Precision Spacing from 5mm to 80mm

    Achieving the exact back focus distance specified by your optical corrector is critical for sharp stars across the entire frame. This 5-piece set allows you to build the exact spacing you need by stacking the 5 mm, 10 mm, 15 mm, 20 mm, and 30 mm tubes. Unlike variable extenders, these fixed-length rings provide a rigid, tilt-free connection that maintains optical alignment, which is essential for modern high-resolution sensors.

    M48 Thread for 2-inch Filter and Flattener Systems

    The M48x0.75 thread, often called the "large T2" or 2-inch filter thread, has become the standard for full-frame imaging trains. These extension tubes feature both male and female M48 threads, allowing them to integrate seamlessly with camera-specific bayonet adapters, correctors, and 2-inch color or nebula filters. Each tube is machined from black anodized aluminum with a large internal diameter to prevent vignetting on camera sensors and a matte finish to absorb stray light.

  • What is the total extension possible with the Explore Scientific M48 Extension Set?

    You can achieve a total extension of 80 mm by threading all 5 rings (30 + 20 + 15 + 10 + 5 mm) together. The set also allows for any 5 mm increment between 5 mm and 80 mm.

    Can I use 2-inch filters with this Explore Scientific M48 Extension Set?

    Yes. The M48x0.75 thread is the standard thread size for 2-inch astronomy filters. You can thread a filter onto the male end of an extension tube or place the tube after the filter in your optical train.

    My flattener requires 55 mm of back focus. Can the Explore Scientific set achieve this?

    Yes, you can achieve exactly 55 mm of spacing with this set. Simply combine the 30 mm, 20 mm, and 5 mm extension tubes to hit the precise distance required by your flattener.

    Will this Explore Scientific extension set cause vignetting with my full-frame DSLR or mirrorless camera?

    This set is designed to minimize vignetting. The M48 thread is larger than the older M42 T-thread standard, and the tubes have a large, clear internal aperture specifically to illuminate larger sensors. While vignetting depends on the entire optical system, these M48 tubes are the correct choice for full-frame setups.

    I am using an off-axis guider with a Schmidt-Cassegrain telescope and need about 12 mm of extra spacing. Can the Explore Scientific set help?

    Absolutely. This set is ideal for fine-tuning the spacing in an SCT imaging train. You can use the 10 mm ring for a close approximation or stack other rings to get closer to your target. The flexibility of having 5 different lengths is a major advantage in these scenarios.

    Are the threads on the Explore Scientific M48 set compatible with M42 T-rings?

    No, they are not directly compatible. This set uses the larger M48x0.75 thread. The standard T-ring uses a smaller M42x0.75 thread. You would need a specific M42-to-M48 adapter to connect these tubes to a standard T-ring.

  • GTIN 811803031852
  • Explore Scientific Warranty