Askar 111F 0.74x Reducer

Askar 111F 0.74x Reducer

Description

The Askar 111F 0.74x Reducer has been specifically developed for the Askar 111F refractor to provide a faster optical system and a wider imaging field.

Once installed, it reduces the telescope focal length to 566 mm and the focal ratio to f/5.1. This configuration increases the field of view while reducing the exposure times required for astrophotography. It is particularly suitable for imaging large nebulae, star clusters and faint or fast-moving celestial objects.

The reducer also incorporates field-flattening correction designed to effectively reduce field curvature and maintain sharp stars from the center to the edges of the image.

The optical system uses a triplet design and supports a 44 mm image circle, making it suitable for full-frame imaging sensors.

The back focus distance is 55 mm measured from the base of the M48 male thread. M68x1 threads on both ends provide a rigid and secure mechanical connection.

The Askar 111F photographic extension tube includes M54x0.75 and M48x0.75 adapters allowing direct connection to the reducer. The rear adapter ring also features an integrated M48x0.75 filter thread compatible with standard 2-inch astronomical filters.

The reducer body is precision CNC machined and supplied with front and rear threaded metal caps to protect the optics from dust when not in use.

Technical Specifications

• Manufacturer: Askar
• Model: 111F 0.74x Reducer
• Compatibility: Askar 111F
• Reduction factor: 0.74x
• Resulting focal length: 566 mm
• Resulting focal ratio: f/5.1
• Optical design: triplet
• Number of lenses: 3
• Integrated field correction
• Image circle: 44 mm
• Full-frame compatible
• Back focus: 55 mm
• Back focus measured from M48 male thread base
• Front thread: M68x1
• Rear thread: M68x1
• Filter thread: M48x0.75
• Compatible with 2-inch astronomical filters
• Compatible with M54x0.75 adapters
• Compatible with M48x0.75 adapters
• Precision CNC machined construction
• Front threaded metal cap included
• Rear threaded metal cap included
• Weight: 0.5 kg

Product introduction

The 0.74× reducer brings the Askar 111F's focal ratio down to F5.1, delivering a faster optical system while incorporating built-in field-flattening correction to effectively eliminate field curvature - ensuring sharp and clear stars from the center to the very edges of the frame. The shorter focal ratio provides a wider field of view and shorter exposure times, making it particularly well-suited for capturing expansive nebulae, star clusters, and faint or fast-moving celestial objects.

 

The Askar 111F 0.74× Reducer features a triplet optical design and supports a 44mm full-frame image circle. Its back focus is 55mm (measured from the M48 thread), and both ends feature M68×1 threads for optimal adaptability and stability.

 

The 111F photographic extension tube includes M54×0.75 and M48×0.75 adapters, allowing for direct and convenient connection to the 111F 0.74× reducer. The reducer’s rear adapter ring features a built-in M48×0.75 standard 2-inch filter thread, enabling direct installation of various astronomical filters to accommodate different imaging needs.

 

The entire reducer is precision CNC-machined and comes with front and rear metal threaded caps to protect the optics from dust when not in use.