Starlight Instruments 3.0" Adapter for Older Astro-Physics 4" Telescopes

This adapter is required to physically connect a Starlight Instruments 3.0" Feather Touch focuser to the optical tube of an Astro-Physics 4" refractor. It is custom-machined to fit the 4.880" inside diameter of the telescope tube, ensuring a secure, perfectly centered fit that a generic adapter cannot guarantee.

No. This adapter is designed exclusively for older Astro-Physics 4" refractors with a 4.880" tube inside diameter. Attempting to use it on other telescopes, even those with similar aperture, will likely result in an improper fit.

Yes. The primary purpose of this adapter is to create a solid, flex-free connection between the telescope and a high-payload focuser like the 3.0" Feather Touch. It is sized for the 4.880" tube and held with 3 set screws, giving demanding imaging trains a secure base.

Installation typically involves unthreading the stock focuser assembly from the rear of the optical tube. The Starlight Instruments adapter then fits into the telescope tube in its place and is held with 3 set screws. Finally, the 3.0" Feather Touch focuser is secured to the adapter.

The rotational capability is a feature of the Feather Touch focuser itself, not the adapter. This adapter provides the fixed, secure mounting point, and the focuser's own rotation mechanism (if equipped) will function as designed once attached.

No. This adapter is a replacement part, not an add-on. It is used to mount a Starlight Instruments 3.0" Feather Touch focuser in place of the original focuser that came with your Astro-Physics telescope.