Takahashi Adapter for Turret 36.5 mm × 2″ (TKA00105)

Takahashi Adapter for Turret 36.5 mm × 2″ (TKA00105)

When you fit the 4-Turret eyepiece holder (TKA00404) to certain Takahashi refractors—such as the FC‑76S, FSQ‑85, FSQ‑106ED, FSQ‑130ED, Mewlon‑250CRS, or Mewlon‑300CRS—you need precisely 36.5 mm of optical extension for proper focus. The TKA00105 is designed specifically for this purpose: a solid, short 2″ extension tube with threaded 2″ filter thread and dual M5 compression screws, all in black-anodized aluminum, ensuring rigidity and zero flex.

At just 36.5 mm of additional back-focus, it positions the turret perfectly, allowing full immersion of the standard 2″ sleeve and leaving room for filters. It’s the only correct spacer for maintaining the optical train integrity when switching to the turret system—no makeshift stacking, no compromises.

Cloudy Nights Insight

Though the adapter itself is rarely the headline in user discussions, many veteran FSQ/FCQ owners stress the importance of the right spacer when using accessories like the 4‑turret: “You must use the 36.5 mm spacer or the system just won’t focus”—a quote echoed in several threads about turret focus issues. That consensus reinforces the TKA00105’s necessity for smooth, reliable eyepiece changes without sacrificing image sharpness or safety.

Observing Tip

Install the TKA00105 between the turret base and your telescope’s rear cell before adding the turret. This ensures the turret rotates freely, eyepieces reach critical sharpness, and your alignment remains stable—even under heavy star charts and multi-eyepiece use. Once the tube is in place, filter access via the front retaining screws is easy and secure.