Coma Corrector Beta MPCC Mark III Photo + Visual 2" for telescopes

The Beta MPCC Mark III Photo + Visual 2" coma corrector is an optical accessory for reflector telescopes that reduces off-axis coma and improves star shapes across the field. Designed for 2-inch focusers, this corrector delivers sharper stars and more uniform image quality toward the edges of the field, making it suitable for both photographic and visual observing. It maintains parfocality with visual eyepieces and photographic cameras when used with appropriate adapters and spacing.

Advantages

The design corrects coma while preserving the native focal ratio of the telescope, enabling wide-field imaging without excessively changing exposure requirements. Improved edge sharpness reduces star elongation and simplifies image processing for astrophotography. Mechanical compatibility with standard 2" focusers and a parfocal visual path allow quick switching between camera and eyepiece use without significant re-focusing.

Suitable for

• Wide-field astrophotography with reflector telescopes
• Visual observing where round stars across the field are desired
• Amateur astronomers using 2" focusers and DSLR or dedicated astronomy cameras
• Observing and imaging with Schmidt-Newtonian and fast Newtonian reflectors

Key specifications

• Optical function: coma correction for reflector telescopes
• Focuser interface: 2" (standard) mechanical mounting
• Use modes: photographic and visual (parfocal with proper spacing)
• Field performance: improves star shapes toward the edge of the field
• Compatibility: designed for fast focal ratios commonly used in wide-field setups

How to use

Install the coma corrector into the telescope's 2" focuser and secure it according to the focuser's locking mechanism. Attach the camera adapter or visual eyepiece to the corrector; for photographic use, ensure the recommended spacing between the corrector and the camera sensor is observed to achieve optimal correction and focus. When switching between camera and eyepiece, minor focus adjustments may be required depending on camera backfocus and adapter thickness.

Usage recommendations

To achieve best results, verify the correct backfocus distance for your specific camera and adapters before a long imaging session. Use a Bahtinov mask or focus aid to obtain precise focus, and perform flat-field calibration in post-processing to correct vignetting or residual field illumination variations.