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Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)

Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)

by Baader Planetarium
SKU BAA-2454833
CA$43.00 - CA$43.00
CA$43.00
CA$43.00 - CA$43.00
CA$43.00
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  • Connects T-2 (M42x0.75) male threaded accessories to 2" SCT female threads
  • Zero optical length design preserves critical back focus spacing
  • Ideal for connecting cameras, filter wheels, and eyepieces to SCTs
  • Prevents spacing errors with focal reducers and field flatteners
  • Specific application: Attach a Hyperion Universal Zoom Mark IV to a T-2 thread
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)

    The Baader Zero Optical Length Adapter provides the most direct and mechanically rigid way to connect T-2 (M42x0.75) threaded accessories to a standard 2" Schmidt-Cassegrain (SCT) visual back. By design, this adapter consumes no additional back focus, making it the essential solution for maintaining the precise spacing required by focal reducers, field flatteners, and other corrective optics. For imagers integrating T-2 equipment like the Hyperion Universal Zoom Mark IV into an SCT optical path, this adapter ensures the system's design spacing remains unaltered.

    Connecting T-2 Accessories to a 2" SCT Visual Back

    This thread reducer bridges the gap between two of the most common standards in astronomy: the 2" SCT thread found on the rear cell of most Schmidt-Cassegrain and Maksutov-Cassegrain telescopes, and the universal T-2 thread used by countless cameras, filter wheels, off-axis guiders, and eyepieces. The adapter features male 2" SCT threads on one side and male T-2 threads on the other, creating a secure, all-threaded connection that eliminates the flexure and potential tilt of slip-fit adapters.

    The Zero Optical Length Design: Preserving Critical Back Focus

    The defining feature of this adapter is its "zero optical length" construction. Unlike standard adapters that add several millimeters to the light path, this component is engineered so that the shoulder of the T-2 accessory seats directly against the SCT visual back. The adapter itself occupies no space along the optical axis, preserving every millimeter of precious back focus.

    This is not a minor convenience—it is critical for optical correctors. Focal reducers and field flatteners are designed to work at a very specific distance from the sensor. Adding an adapter with even 5-10mm of optical length can introduce significant aberrations, ruining image sharpness. This adapter solves that problem by making the mechanical connection without changing the optical spacing.

  • What does "Zero Optical Length" mean for the Baader 2"/T-2 Adapter?

    It means the adapter itself adds no length to your telescope's light path. It facilitates the mechanical connection between the 2" SCT thread and the T-2 thread without consuming any of your available back focus, which is critical for astrophotography with reducers or flatteners.

    How does the Baader Zero Optical Length Adapter help when using a focal reducer on my 8" SCT?

    SCT focal reducers require a precise distance to the camera sensor to function correctly. A standard adapter would add to this distance, potentially causing distorted stars at the edge of your field. The Baader Zero Optical Length adapter allows you to connect your T-2 threaded camera or filter wheel without altering that critical spacing, ensuring your reducer performs as designed.

    I want to attach a Hyperion Universal Zoom Mark IV to my telescope's 2" SCT visual back. Is this the right adapter?

    Yes, this is a primary use case for this adapter. It allows you to directly and securely thread the Hyperion Zoom (which has T-2 threads) onto an SCT, providing a solid connection without the need for a 2" nosepiece and diagonal.

    Can I use this Baader adapter to connect my T-2 threaded DSLR T-ring to my SCT?

    Absolutely. This adapter is the ideal way to connect a standard T-ring to your SCT for prime-focus astrophotography. It creates an all-threaded, rigid connection from the telescope to your camera body, minimizing flexure.

    What problem does the Baader Zero Optical Length Adapter solve that a standard adapter doesn't?

    Standard adapters add physical length to the imaging train, which can prevent you from reaching focus or, more commonly, violate the strict spacing requirements of optical correctors. This adapter solves that by making a purely mechanical connection that is optically invisible in terms of path length.

    What are the threads on the Baader 2" SCT to T-2 adapter?

    The adapter has male (external) 2" SCT threads on the telescope side and male (external) T-2 (M42x0.75) threads on the accessory side. It is designed to thread into a female 2" SCT port and accept a female T-2 threaded accessory.

  • Net weight (kg) 0.01
    Compatible Brands Astro T-2, Baader Planetarium
    Inner Diameter / Clear Aperture (mm) 41
    Outer Diameter 50.8mm (2" SC)
    Type of Adapter Reducing Adapter
    Inner Connection (eyepiece/-camera-sided) M42 x 0.75 (T-2)
    Outer Connection (eyepiece/-camera-sided) 2"/SCT Thread (50.8mm)
    Inner Connection (lens sided) M42 x 0.75 (T-2)
    Outer Connection (lens sided) 2"/SCT Thread (50.8mm)
  • Baader Planetarium Warranty