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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.

Starlight Instruments 3.0" End Cap - M48X.75(M)

by Starlight Instruments
SKU SI-EC30-1905-48
$150.00 - $150.00
$150.00
$150.00 - $150.00
$150.00
Price Match Policy!
  • Fits 3.0" Feather Touch Focusers
  • Provides Male M48x0.75 Threaded Connection
  • Ideal for 2" Filters, Field Flatteners, and Reducers
  • Creates a Rigid, Zero-Tilt Imaging Train
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  • Description
  • FAQ
  • In the Box
  • Downloads
  • Warranty

  • Starlight Instruments 3.0" End Cap - M48X.75(M)

    The Starlight Instruments 3.0" End Cap with M48x0.75 male threads replaces the standard compression ring on your Feather Touch focuser, creating a solid, direct-thread connection for your imaging train. This interface is essential for securely attaching 2-inch filters, field flatteners, and correctors like the TOA 1.6X extender to your 3.0" Feather Touch system without introducing flexure.

    Secure M48x0.75 Threading for Critical Imaging Connections

    This end cap provides a male M48x0.75 thread, the universal standard for most 2-inch astronomy filters and a wide array of popular field flatteners and reducers. It allows you to build a rigid, perfectly aligned optical train from the drawtube of your 3.0" Feather Touch focuser directly to your accessories. This is the specified part for connecting devices that demand precise spacing and orthogonality, ensuring your corrector lenses perform exactly as designed.

    Threaded vs. Compression: Eliminating Tilt in Your 3.0" Focuser

    While a standard 2-inch compression ring end cap offers convenience for swapping visual eyepieces, it can introduce minute amounts of tilt, especially with heavier cameras or filter wheels. This M48x0.75 threaded end cap eliminates that variable by creating a solid, metal-to-metal junction. For astrophotography with a high-end 3.0" Feather Touch focuser, this rigidity is non-negotiable for achieving a perfectly flat field from corner to corner.

  • What is the Starlight Instruments M48x0.75 End Cap used for?

    This end cap is designed to replace the standard 2" compression ring on a Starlight Instruments 3.0" Feather Touch focuser. It provides a solid M48x0.75 male thread for directly attaching accessories like 2" filters, field flatteners, reducers, or other correctors to create a rigid, tilt-free imaging train.

    Will this M48x0.75 End Cap fit my 2.0" Feather Touch focuser?

    No, this end cap is specifically designed for the larger 3.0" Feather Touch focusers. Starlight Instruments makes different end caps for their 2.0", 2.5", and 3.5" focuser models. You must use the end cap that matches your focuser's body size.

    Why should I use this threaded End Cap instead of the standard compression ring on my 3.0" Feather Touch?

    For astrophotography, a threaded connection is always superior to a compression ring. It completely eliminates the possibility of tilt or sag in the optical train, which is critical for maintaining a flat field with sensitive, large-format cameras. While a compression ring is fine for visual use, this threaded cap provides the mechanical rigidity serious imaging demands.

    How do I attach a 2" filter to my imaging train using this Starlight Instruments End Cap?

    The M48x0.75 thread on this end cap is the same as a standard 2" filter thread. You can thread a 2" filter directly onto this end cap. Alternatively, you can place it at the front of your field flattener or other M48-threaded accessory before attaching that accessory to the end cap.

    Is this the correct part for connecting a Takahashi TOA 1.6x extender to my Feather Touch 3.0" focuser?

    Yes, this end cap is an appropriate component for connecting accessories with a female M48x0.75 thread, such as the TOA 1.6x extender, to a Starlight Instruments 3.0" focuser. It ensures a secure and properly aligned connection.

    Does this Starlight Instruments end cap add significant length to the optical train?

    This end cap is a low-profile replacement for the original end cap and is designed to take up minimal back focus. However, any change to your imaging train requires you to verify your back focus spacing. Always measure the distance from your sensor to your last optical element to ensure it matches the manufacturer's specification.

    • 3.0" End Cap with M48x0.75 Male Thread

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  • Starlight Instruments 2-Year Warranty