Flattener Skywatcher Evoguide 50 SW-5414 — field flattener for 50 mm refractors

Skywatcher Evoguide 50 SW-5414 is a field flattener engineered for 50 mm refractor telescopes. It reduces field curvature and improves point-source sharpness across the imaging circle, making stars appear sharper from centre to edge. The flattener fits between the telescope's focuser and the camera or eyepiece and is compatible with the Evoguide series optical train. It is intended for wide-field astrophotography where edge sharpness and uniform star images are required.

Advantages

The Skywatcher Evoguide 50 delivers a flatter focal plane and better edge-to-edge sharpness compared with plain refractor optics, reducing star elongation and coma at the frame borders. Its optical design preserves contrast and minimizes additional aberrations when used within the specified backfocus range. Mechanical mounting is straightforward for standard 50 mm guide scopes and dedicated Evoguide accessories, allowing reliable repeatable connection between telescope and imaging device.

Suitable for

• Wide-field deep-sky imaging with 50 mm refractors
• Planetary and lunar imaging where uniform star points are desired
• Guide-scope setups in small refractor imaging trains
• Astrophotographers seeking improved edge-to-edge star sharpness

Key specifications

• Optical purpose: field flattener for 50 mm refractor telescopes
• Compatible telescope aperture: 50 mm guide and refractor tubes
• Designed mounting position: between focuser and camera/eyepiece
• Effect: corrects field curvature to improve edge sharpness
• Application: wide-field astrophotography and guiding

How to use

Install the flattener directly into the focuser or adapter designed for the Evoguide series, then attach the camera or eyepiece to the flattener's output. Ensure the optical spacing (backfocus) recommended for the Evoguide 50 is observed to achieve the intended field flattening; adjust the camera's position along the imaging train until stars are round across the frame. Balance and collimate the telescope as required for your imaging setup and perform usual focus and framing adjustments before starting exposures.

Usage recommendations

For best results, verify the mechanical spacing between the flattener and camera sensor according to Skywatcher Evoguide guidance, use software-assisted focusing and check stars at the frame corners during initial setup. When combining with additional adapters or extension tubes, test and re-check field sharpness and re-focus as necessary.