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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.
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.

Starlight Instruments 1.25" Adapter for Astro-Tech 6", 8" and GSO 6", 8" RC Telescope

by Starlight Instruments
SKU SI-A15-1503-2
$50.00 - $50.00
$50.00
$50.00 - $50.00
$50.00
Price Match Policy!
  • Enables use of 1.25" eyepieces and accessories
  • Designed for Astro-Tech & GSO 6" and 8" Ritchey-Chrétien telescopes
  • Features a secure 90x1mm female thread
  • Precision-machined by Starlight Instruments for a zero-flexure fit
  • Low profile design minimizes impact on back focus
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Starlight Instruments 1.25" Adapter for Astro-Tech & GSO RC Telescopes

    The Starlight Instruments 1.25" Adapter provides a direct, threaded connection for your 1.25" eyepieces and accessories to Astro-Tech and GSO 6" and 8" Ritchey-Chrétien telescopes. It features a female 90x1mm thread for a secure, zero-flexure attachment to the rear cell of these popular imaging scopes, converting them for high-quality visual use.

    Secure 1.25" Accessory Connection via 90x1mm Thread

    Unlike generic slip-fit adapters that can introduce tilt and image shift, this Starlight Instruments adapter threads directly onto the 90x1mm male threads found on the focusers or extension tubes of Astro-Tech and GSO 6" and 8" RC telescopes. This rigid, all-metal connection ensures your eyepieces and small cameras are held perfectly parallel to the optical axis, preserving the sharp, flat field these Ritchey-Chrétien optics are known for.

  • What is the thread size on the Starlight Instruments 1.25" Adapter for Astro-Tech RCs?

    This adapter features a 90x1mm female thread on the telescope side, designed to attach to the corresponding male thread on the focuser or rear cell of compatible telescopes.

    Which telescopes is this Starlight Instruments 1.25" adapter compatible with?

    It is specifically designed for Astro-Tech and GSO 6" and 8" Ritchey-Chrétien telescopes. You should always verify that your telescope's visual back or focuser has a 90x1mm male thread before purchasing.

    Can I use this Starlight Instruments adapter for visual observing on my GSO 8" RC?

    Yes, absolutely. This adapter's primary purpose is to allow you to use standard 1.25" eyepieces for visual astronomy with your 8" GSO RC. It provides the secure, threaded connection needed for a stable and sharp view.

    Will this adapter let me reach focus with my eyepieces on an Astro-Tech 6" RC?

    This adapter provides the correct mechanical connection. Achieving focus with your Astro-Tech 6" RC will still depend on the telescope's back focus and your specific eyepiece. Ritchey-Chrétien telescopes often require using a specific combination of extension tubes to place the eyepiece at the focal plane, and you may need to add or remove extenders to suit your setup.

    Why use this threaded Starlight Instruments 1.25" adapter instead of a generic slip-in adapter?

    A threaded connection is mechanically superior. It completely prevents the possibility of tilt or wobble that can occur with adapters held in place by a single thumbscrew. This rigidity is crucial for maintaining the precise optical alignment of your RC telescope and achieving the sharpest possible images.

    How does the Starlight Instruments adapter hold a 1.25" eyepiece in place?

    The adapter has a 1.25" barrel receiver. Eyepieces and accessories are typically secured within this barrel by one or more thumbscrews. Starlight Instruments components are machined to tight tolerances for a precise, non-slip fit.

  • Accessory Compatibility 1.25" Eyepieces & Accessories
    Telescope-Side Connection 90x1mm Female Thread
    Telescope Compatibility Astro-Tech 6" & 8" RC, GSO 6" & 8" RC

    • 1.25" Adapter for Astro-Tech/GSO RC Telescopes

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  • Starlight Instruments 2-Year Warranty