Hotech 2" SCA field flattener (22937)

Hotech Field Flattener – Flat and Sharp Astrophotography to the Edge of the Image

Refractor telescopes often produce optical errors toward the edge of the image field. This leads to field curvature, where stars near the edges appear blurred, distorted, or out of focus. Such curvature reduces image quality and is especially undesirable in astrophotography, where visual aesthetics and pinpoint stars matter. The Hotech Field Flattener offers a simple and effective solution to this common issue.

Same Focal Length with a Perfectly Flat Field

Achieving sharp stars right to the corners of the image is possible with the Hotech Field Flattener—and it is remarkably easy to use. This compact, well-designed accessory can be attached to both apochromatic and achromatic refractors. It is optimized for telescopes with focal ratios between f/5 and f/8. Unlike many field flatteners, it does not alter the focal length of your telescope, allowing you to maintain your original imaging scale.

Precise Self-Centering Design

A field flattener is only effective if it is perfectly aligned. Even slight tilting in the focuser can introduce optical errors. To address this, the Hotech Field Flattener features a patented self-centering mechanism. Simply insert the 2-inch adapter into the focuser and rotate the integrated ring until the compression system locks the flattener securely in place. This design eliminates tilt caused by side screws and compensates for mechanical tolerances in 2-inch focusers, resulting in improved image quality and consistency.

Key Advantages

• Suitable for refractor telescopes with focal ratios from f/5 to f/8

• Produces a completely flat image field, right to the corners

• Multi-coated optical surfaces for effective anti-reflection performance

• No tilting thanks to the 2-inch self-centering sleeve

• 2-inch plug-in sleeve with T-2 thread on the camera side

• Requires a back focus distance of 55 mm from the rear stop to the camera sensor

Technical Specifications

Compatibility and Optics

• Suitable for: Refractors with f/5 to f/8 focal ratios

• Optical coating: Multi-coated

• Focal length reduction: None

• Focal length extension: None

Connections and Mounting

• Telescope connection: 2-inch

• Camera-side connection: T-2 thread

• Filter thread: Yes

General Information

• Product type: Field flattener

• Category: Flatteners, correctors, reducers

• Color: Black

Dimensions and weight are not specified by the manufacturer.