Eyepiece Projection OPFA IV with T-2i thread

Eyepiece Projection OPFA IV with T-2i thread

Description

The OPFA IV eyepiece projection adapter with T-2i thread is Baader’s base version for classic eyepiece projection photography. It is designed for digital or analog SLR cameras with removable lenses and connects exclusively through standard T-2 threads (M42 x 0.75), making it universally compatible with T-2-based setups. This version is ideal for custom configurations where no fixed telescope nosepiece is required.

This model includes the OPFA sliding focuser (#2458010), which holds a 31.75 mm projection eyepiece (not included) and allows fine axial positioning of the eyepiece for precise control of the projection distance. This is essential for adjusting the equivalent focal length (fE) according to the formula: fE = fprimary × ((a ÷ fEP) - 1), where a is the distance between the eyepiece and the camera sensor, and fEP is the eyepiece focal length. Larger distances or shorter focal lengths yield greater magnification.

Two 40 mm T-2 extension tubes (#1508153) are included. These can be combined with additional T-2 extensions to further increase the projection scale. The camera connects via a T-2 ring specific to the camera model (not included).

The OPFA IV offers a rigid, light-tight, and play-free mechanical connection, ensuring perfect alignment between the telescope’s optical axis and the camera sensor. This version has no nosepiece, making it ideal for users whose telescopes already provide a T-2 threaded output. It is also suited for building more complex setups requiring flexible T-2 integration.

A locking ring integrated into the sliding focuser allows for stepless rotation of the camera, enabling ideal image orientation without misalignment, especially useful during high-magnification imaging.

The 38 mm internal diameter supports standard eyepieces without significant vignetting. The assembly is precisely machined for excellent mechanical stability. This version is recommended for planetary or lunar photography using SC, Newtonian, or any telescope with a T-2 output, and for CCD projection setups requiring exact mechanical alignment.

Technical specifications

• Base version OPFA with full T-2 threaded connections

• Telescope-side connection: T-2 female thread (M42 x 0.75)

• Camera-side connection: T-2 male thread (M42 x 0.75)

• Compatible with all T-2 threaded telescope accessories

• OPFA sliding focuser for 31.75 mm eyepieces

• Fine axial adjustment of eyepiece position

• Integrated locking ring for stepless camera rotation

• Includes two 40 mm T-2 extension tubes (#1508153)

• Eyepiece not included

• Camera-specific T-2 ring not included

• Internal diameter: 38 mm

• Outer diameter: 60 mm

• Optical length: variable depending on configuration

• Net weight: 0.15 kg

• Rigid, light-tight, vibration-free construction

• Compatible with Baader Astro T-2 system for extension