What specific focuser does the Starlight Instruments 3.5" End Cap fit?
This end cap is designed exclusively for the Starlight Instruments 3.5" Feather Touch focuser series. It is a direct replacement for the focuser's original end cap and will not fit other brands or sizes.
Which focal reducer is this M82x1 End Cap designed for?
This cap is specifically machined with M82x1 female threads to connect the APM/TMB .75x Reducer. It is not compatible with reducers that use a different thread size or connection method.
How does this Starlight Instruments End Cap prevent flexure when imaging with my APM refractor and the .75x reducer?
By creating a direct, rigid threaded connection between the 3.5" Feather Touch focuser and the APM/TMB .75x reducer, it eliminates potential sag or tilt that can occur with less precise adapters. This is critical for maintaining a flat field and sharp stars to the edge of your camera's sensor.
Is installation of this 3.5" End Cap difficult?
Installation is straightforward for the end-user. You simply unthread the existing end cap from your 3.5" Feather Touch focuser and carefully thread this new one in its place. Ensure the threads are clean and engage smoothly to avoid cross-threading.
Why choose this Starlight Instruments End Cap over a generic adapter?
Starlight Instruments machines this cap in-house from high-grade aluminum to the same exacting tolerances as their focusers. This guarantees perfect optical alignment and a secure fit, protecting your investment in both the focuser and the APM/TMB reducer and preventing image-degrading tilt.
Can I use this end cap to attach my camera directly to my 3.5" Feather Touch focuser for imaging M31?
No, this end cap is not a camera adapter. Its M82x1 female thread is specifically for attaching the APM/TMB .75x Reducer. To attach a camera, you would need a different set of adapters that provide the correct thread (e.g., M48) and back focus spacing, which would typically be attached after the reducer.
