Long Perng 2” 0.6x Field Flattener / Reducer for f/5 - f/7 Refractor Telescopes (with M48 Thread)

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- Long Perng 2” 0.6x focal reducer/field flattener for refractors of focal ratio f/5 to f/7
- Flattens image field for cameras with APS-C or smaller sensors
- Integrated M48 thread for camera attachment (an M42 T/T2 version of this reducer is also available separately)
- CNC machined body with hard, gloss, black anodized finish.
- Features 2" nosepiece with safety groove
- Requires 55mm back focus
The Long-Perng 0.6x focal reducer/field flattener # K0.6X-BU minimizes field curvature caused by the objective lenses of fast refractors and provides a sharper image across the camera sensor. It also reduces the effective focal length of a telescope by 0.6x to allow wider-field imaging and faster exposure times.
The optical design of this reducer/flattener makes it optimal for use with refractors with a focal ratio of approximately f/5 to f/7 when used with an APS-C sensor. With smaller sensor 1” and 4/3” cameras, it can work well with refractors slightly outside this range of focal ratio.
With male M48x0.75 threads to interface with the camera, this 2” reducer/flattener delivers an image circle of 42mm, almost large enough for use with full-frame cameras (although the use of sensors larger than APS-C is not recommended). An M42 T/T2 threaded version of this item is also sold separately if you need the smaller camera interface.
The flattener’s nosepiece slides into any standard 2” telescope focuser. Note: The nosepiece has a female M48x0.6 thread on the telescope side and will only accept Orion 2” filters - it will NOT accept most other 2” filters on the market which use the more common M48x0.75 threads.
The Long Perng 2” 0.6x reducer/flattener requires a standard back focus of 55mm from the base of the male M48 thread. This makes it ideal for DSLR cameras with a wide M48 T-ring (sold separately). It also works with most other astronomy cameras when matched with suitable extension rings (sold separately).
This reducer/flattener features fully multi-coated optics in an anodized CNC-machined aluminum body with a polished gloss black finish.
Other Information
- Country of Manufacture: Taiwan
The Long-Perng 0.6x focal reducer/field flattener # K0.6X-BU minimizes field curvature caused by the objective lenses of fast refractors and provides a sharper image across the camera sensor. It also reduces the effective focal length of a telescope by 0.6x to allow wider-field imaging and faster exposure times.
The optical design of this reducer/flattener makes it optimal for use with refractors with a focal ratio of approximately f/5 to f/7 when used with an APS-C sensor. With smaller sensor 1” and 4/3” cameras, it can work well with refractors slightly outside this range of focal ratio.
With male M48x0.75 threads to interface with the camera, this 2” reducer/flattener delivers an image circle of 42mm, almost large enough for use with full-frame cameras (although the use of sensors larger than APS-C is not recommended). An M42 T/T2 threaded version of this item is also sold separately if you need the smaller camera interface.
The flattener’s nosepiece slides into any standard 2” telescope focuser. Note: The nosepiece has a female M48x0.6 thread on the telescope side and will only accept Orion 2” filters - it will NOT accept most other 2” filters on the market which use the more common M48x0.75 threads.
The Long Perng 2” 0.6x reducer/flattener requires a standard back focus of 55mm from the base of the male M48 thread. This makes it ideal for DSLR cameras with a wide M48 T-ring (sold separately). It also works with most other astronomy cameras when matched with suitable extension rings (sold separately).
This reducer/flattener features fully multi-coated optics in an anodized CNC-machined aluminum body with a polished gloss black finish.
- Long Perng 2” 0.6x focal reducer/field flattener for refractors of focal ratio f/5 to f/7
- Flattens image field for cameras with APS-C or smaller sensors
- Integrated M48 thread for camera attachment (an M42 T/T2 version of this reducer is also available separately)
- CNC machined body with hard, gloss, black anodized finish.
- Features 2" nosepiece with safety groove
- Requires 55mm back focus
The Long-Perng 0.6x focal reducer/field flattener # K0.6X-BU minimizes field curvature caused by the objective lenses of fast refractors and provides a sharper image across the camera sensor. It also reduces the effective focal length of a telescope by 0.6x to allow wider-field imaging and faster exposure times.
The optical design of this reducer/flattener makes it optimal for use with refractors with a focal ratio of approximately f/5 to f/7 when used with an APS-C sensor. With smaller sensor 1” and 4/3” cameras, it can work well with refractors slightly outside this range of focal ratio.
With male M48x0.75 threads to interface with the camera, this 2” reducer/flattener delivers an image circle of 42mm, almost large enough for use with full-frame cameras (although the use of sensors larger than APS-C is not recommended). An M42 T/T2 threaded version of this item is also sold separately if you need the smaller camera interface.
The flattener’s nosepiece slides into any standard 2” telescope focuser. Note: The nosepiece has a female M48x0.6 thread on the telescope side and will only accept Orion 2” filters - it will NOT accept most other 2” filters on the market which use the more common M48x0.75 threads.
The Long Perng 2” 0.6x reducer/flattener requires a standard back focus of 55mm from the base of the male M48 thread. This makes it ideal for DSLR cameras with a wide M48 T-ring (sold separately). It also works with most other astronomy cameras when matched with suitable extension rings (sold separately).
This reducer/flattener features fully multi-coated optics in an anodized CNC-machined aluminum body with a polished gloss black finish.
Other Information
- Country of Manufacture: Taiwan

Long Perng 2” 0.6x Field Flattener / Reducer for f/5 - f/7 Refractor Telescopes (with M48 Thread)
