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Starlight Instruments 3.5" End Cap w/ M48X.75 Threads
The Starlight Instruments 3.5" End Cap provides a direct male M48x0.75 threaded connection for all 3.5" Feather Touch focusers. This component replaces the standard compression ring adapter, creating a direct threaded attachment point for heavy imaging trains that utilize the common M48x0.75 filter thread standard.
A Secure M48x0.75 Interface for Your 3.5" Feather Touch Focuser
For serious astrophotography, a threaded connection is non-negotiable. This M48x0.75 end cap gives a direct thread connection for field flatteners, filters, the Takahashi TOA 1.6X extender or any other accessory with this thread. A threaded connection holds the accessory more securely than a thumbscrew-based adapter.
M48 Threaded Connection vs. 2" Compression Ring: Why It Matters for Imaging
While a standard 2" compression ring offers convenience for swapping visual eyepieces, it introduces a mechanical weak point for imaging. A threaded connection holds the accessory more firmly, helping keep the camera square to the optical axis through a long exposure, whatever the telescope's orientation. This prevents elongated stars in the corners of your frames, a common artifact of component tilt in an imaging train secured by compression rings or set screws.
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What is the primary purpose of the Starlight Instruments 3.5" M48 End Cap?
Its primary purpose is to provide a solid, threaded M48x0.75 connection point on a 3.5" Feather Touch focuser. It holds accessories more securely than a compression ring adapter, which matters most with heavy cameras or accessories.
How does this M48 End Cap for the 3.5" Feather Touch prevent image tilt?
By threading directly onto your camera, field flattener, or other M48-threaded accessory, the Starlight Instruments End Cap creates a single, rigid unit with the focuser drawtube. Unlike a compression ring which holds an accessory with friction and thumbscrews, this direct threaded connection holds the accessory firmly. Most Starlight end caps also have 3 set screws on the face for fine tilt (collimation) adjustment with a 1/16 hex key.
Will this Starlight Instruments End Cap fit focusers other than the 3.5" Feather Touch?
No, this end cap is specifically designed to fit the drawtube of Starlight Instruments 3.5" Feather Touch focusers. It is not compatible with other sizes or brands of focusers.
How do I attach my 2" light pollution filter using the Starlight Instruments M48 End Cap?
The M48x0.75 thread on this end cap is the same standard used for 2" filters. Filters are among the accessories that thread directly onto this end cap, along with field flatteners and the Takahashi TOA 1.6X extender. This ensures the filter is securely held within the rigid imaging train.
When should I choose this M48 threaded end cap over the standard 2" compression ring on my Feather Touch focuser?
You should choose the M48 threaded end cap for any astrophotography application. The standard 2" compression ring is sufficient and more convenient for visual observing where small amounts of tilt are unnoticeable. For imaging, the rigidity of a threaded connection is critical for sharp, round stars across the entire frame.
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| Compatibility |
Starlight Instruments 3.5" Feather Touch Focusers |
| Thread Type |
M48x0.75 Male |
| Kind |
Threaded focuser end cap |
| Telescope-side connection |
3.5" Feather Touch drawtube |
| Fits |
Field flatteners, filters, Takahashi TOA 1.6X extender (M48x0.75) |
| Material |
Aluminum |
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3.5" End Cap w/ M48X.75 Threads
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- Starlight Instruments 2-Year Warranty
