What is the purpose of the Starlight Instruments 3.5" End Cap for Takahashi 72mm accessories?
Its primary purpose is to provide a secure, threaded connection between a 3.5" Starlight Instruments Feather Touch focuser and Takahashi accessories, such as field flatteners or reducers, that have a male 72mm x 1mm thread. This is critical for astrophotography to prevent tilt and flexure in the imaging train.
How does this 72mm End Cap improve on a standard compression ring adapter?
A threaded connection is far more rigid and secure than a compression ring. For heavy imaging trains, this end cap eliminates the potential for sag, tilt, or rotation, ensuring the camera sensor remains perfectly aligned with the optical axis throughout an exposure.
Will this Starlight Instruments End Cap fit my Takahashi FSQ-106ED's stock focuser?
No. This end cap is designed to thread onto the drawtube of a Starlight Instruments 3.5" Feather Touch focuser. It adapts the Starlight focuser to accept Takahashi accessories, not the other way around.
I have a Takahashi TOA-130 with a Starlight 3.5" focuser. Is this the right part for my Takahashi flattener?
You must check the specific thread on your flattener. This end cap has a female M72x1 thread. If your Takahashi flattener or reducer has a matching male M72x1 thread for connection, then this adapter is the correct component to attach it to your 3.5" Feather Touch focuser.
Is installation of this 3.5" End Cap difficult?
Installation is straightforward. It typically involves unthreading the existing end cap (like a 2" compression ring) from the drawtube of your 3.5" Feather Touch focuser and simply threading this new cap in its place until it is snug.
Does this Starlight Instruments End Cap allow for collimation or tilt adjustment?
Starlight does not say whether this end cap has collimation set screws, although its 3.5" focuser manual notes that most of its end caps have 3 set screws for collimation adjustment. Contact us to confirm before relying on it for tilt adjustment.
